Study Evaluating NEOadjuvant Immunotherapy in Resectable PANCreatic Ductal Adenocarcinoma

Inclusion Criteria: * Histological or pathological confirmation of pancreatic adenocarcinoma Cytologic or histologic proof of PDA needs to be verified by the treating institution pathologist either from the initial diagnostic biopsy, or from the required pre treatment biopsy and prior to initiation of any study-related therapy * Extent of disease. Stage 1 or 2 PDA and patient deemed a surgical candidate by the PI in consultation with the designated site radiologist and surgeon at the treating institution * No prior surgical, systemic or radiotherapy for PDA. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Minimum age of at least 18 years. * Adequate hematological and end-organ function, defined by laboratory test results, obtained within 14 days prior to initiation of study treatment: * Tumor accessible for fresh biopsy * Women of child-bearing potential must have a negative serum pregnancy test at screening and must agree to use two forms of effective contraception from the time of the negative pregnancy test and for a minimum of 5 months after the last dose of study drug. Women will be considered not of child-bearing potential if amenorrheic at least for one year or have undergone surgical sterilization. * Fertile men must agree to use an effective method of birth control during the study and for up to 5 months after the last dose of study drug. * Willingness and ability to provide written informed consent prior to any study-related procedures and to comply with all study requirements. * Able to comply with the study protocol, in the investigator's judgment. Exclusion Criteria: * Prior treatment with T-cell co-stimulating or immune checkpoint blockade therapies, including but not limited to anti-CTLA-4, anti-PD-1, and anti-PD-L1 therapeutic antibodies. * Patients who are receiving any other investigational agents concurrently. * Concomitant treatment with other anti-neoplastic agents (hormonal therapy acceptable). * Uncontrolled pleural effusion, pericardial effusion, or ascites. * Patient receiving therapeutic doses of anticoagulation. * Uncontrolled hypercalcemia or symptomatic hypercalcemia requiring continued use of bisphosphonate therapy. * Active or history of autoimmune disease or immune deficiency, including, but not limited to, myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, antiphospholipid antibody syndrome, Wegener granulomatosis, Sjögren's syndrome, Guillain-Barré syndrome, or multiple sclerosis, with the following exceptions: * Patients with a history of autoimmune-related hypothyroidism who are on thyroid replacement hormone are eligible for the study. * Patients with controlled Type 1 diabetes mellitus who are on a stable insulin regimen are eligible for the study. * Patients with eczema, psoriasis, lichen simplex chronicus, or vitiligo with dermatologic manifestations only (e.g., patients with psoriatic arthritis are excluded) are eligible for the study provided all of following conditions are met: * Rash must cover \< 10% of body surface area. * Disease is well controlled at baseline and requires only low-potency topical corticosteroids. * No occurrence of acute exacerbations of the underlying condition requiring psoralen plus ultraviolet A radiation, methotrexate, retinoids, biologic agents, oral calcineurin inhibitors, or high-potency or oral corticosteroids within the previous 12 months. * History of idiopathic pulmonary fibrosis, interstitial lung disease, organizing pneumonia (e.g., bronchiolitis obliterans), drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan * History of radiation pneumonitis in the radiation field (fibrosis) is permitted * Positive HIV test at screening or at any time prior to screening. Patients without a prior positive HIV test result will undergo an HIV test at screening, unless not permitted per local regulations. * Active hepatitis B virus (HBV) infection (chronic or acute) * Active hepatitis C virus (HCV) infection * Known active tuberculosis. * Severe infection within 4 weeks prior to initiation of study treatment * Treatment with therapeutic oral or IV antibiotics within 2 weeks prior to initiation of study treatment except for biliary tract infection due to bile duct obstruction from the pancreas mass. Patients receiving prophylactic antibiotics (e.g., to prevent a urinary tract infection or chronic obstructive pulmonary disease exacerbation) are eligible for the study. * Significant cardiovascular disease (such as New York Heart Association Class II or greater cardiac disease, myocardial infarction, or cerebrovascular accident) within 12 months prior to initiation of study treatment, seizure disorder, uncontrolled hypertension, or unstable arrhythmia or unstable angina within 3 months prior to initiation of study treatment. * Grade ≥3 hemorrhage or bleeding event within 28 days prior to initiation of study treatment. * Prior autologous stem cell, allogeneic stem cell, or solid organ transplantation. * History of malignancy other than PDA within 2 years prior to screening, with the exception of those with a negligible risk of metastasis or death (e.g., 5-year overall survival of \> 90%), such as adequately treated carcinoma in situ of the cervix, nonmelanoma skin carcinoma, localized prostate cancer, ductal carcinoma in situ, or Stage I uterine cancer. Patients with history of prior malignancies should have risk of recurrence within 3 years after screening to be less than 90% (to be discussed with the PI for final determination of eligibility). * Treatment with a live, attenuated vaccine within 4 weeks prior to initiation of study treatment, or anticipation of need for such a vaccine during treatment with atezolizumab or within 5 months after the last dose of atezolizumab. * History of severe allergic anaphylactic reactions to chimeric or humanized antibodies or fusion proteins. * Known hypersensitivity to Chinese hamster ovary cell products or recombinant human antibodies. * Known allergy or hypersensitivity to any of the study drugs or any of their excipients. * Treatment with systemic immunostimulatory agents (including, but not limited to, interferon and interleukin 2) within 4 weeks or five half-lives of the drug (whichever is longer) prior to initiation of study treatment. * Treatment with systemic immunosuppressive medication (including, but not limited to, corticosteroids, cyclophosphamide, azathioprine, methotrexate, thalidomide, and anti-tumor necrosis factor alpha agents) within 2 weeks prior to initiation of study treatment, or anticipation of need for systemic immunosuppressive medication during the course of the study, with the following exceptions: * Patients who received mineralocorticoids (e.g., fludrocortisone), corticosteroids for chronic obstructive pulmonary disease or asthma, or low-dose corticosteroids for orthostatic hypotension or adrenal insufficiency are eligible for the study if receiving equivalent to less than 10mg of prednisone daily. * Patients who received a one-time pulse dose of systemic immunosuppressant medication are eligible for the study after approval from the PI has been obtained. * Inability to swallow medication or malabsorption condition that would alter the absorption of orally administered medications. * Pregnant women are excluded from this study because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with these agents and breastfeeding should be discontinued. * Major surgical procedure or significant traumatic injury within 14 days of initiating study. * Previous radiotherapy to 25% or more of the bone marrow. * Any other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding that contraindicates the use of an investigational drug, may affect the interpretation of the results, or may render the patient at high risk from treatment complications in the opinion of the treating investigator. * Considered ineligible to receive full standard dose modified FOLFIRINOX therapy in the adjuvant setting. * Peripheral neuropathy \> Grade 1 * History of allergy or hypersensitivity to oxaliplatin, irinotecan, leucovorin, fluorouracil, pegfilgrastim, or any excipients. * History of Gilbert's disease or known genotype UGT1A1 \* 28/\* 28.6.2.35 Inflammatory disease of the colon or rectum, or severe uncontrolled diarrhea. Exclusion Criteria for PEGPH20-Containing Arm Patients who meet any of the following criteria will be excluded from the PEGPH20- containing arm: * History of transient ischemic attack requiring intervention or treatment, carotid artery disease requiring interventions or treatment, of cerebrovascular accident * Evidence of deep vein thrombosis (DVT), pulmonary embolism, or other thromboembolic event at screening, except: * Superficial vein thrombosis * Visceral or splanchnic vein thrombosis if the thrombosis is at a location near the site of underlying pancreatic ductal adenocarcinoma (PDAC) which may contribute to the etiology of the thrombus * Treatment with megestrol acetate within 14 days prior to initiation of study treatment * Unable to use low-molecular-weight heparin Criteria to initiate chemotherapy * Full recovery from surgery and subject able to receive chemotherapy. * Subjects who have evidence of recurrent disease prior to initiation of chemotherapy will need to undergo biopsy to prove disease recurrence if deemed safe. * Hematological: laboratory test results within protocol defined safety limits