GVAX Pancreas Vaccine (With CY) in Combination With Nivolumab and SBRT for Patients With Borderline Resectable Pancreatic Cancer

Inclusion Criteria: * Have histologically proven pancreatic cancer that is borderline resectable * No more than 1 month/cycle (28 days) of systemic therapy for pancreatic cancer * Age \>18 years old. * Eastern Cooperative Oncology Group (ECOG) performance status 0-1. * Patients must have adequate organ and marrow function defined by study-specified laboratory tests. * Woman of child bearing potential must have a negative pregnancy test. * Must use an acceptable form of birth control while on study. * Must be candidate for Stereotactic Body Radiation Therapy (SBRT) * Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Had major surgery within the last 28 days * Had an investigational drug or device within the past 28 days * Prior treatment with immunotherapy agents (including, anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CTLA4, etc) * Completed more than 1 month/cycle (28 days) of chemotherapy for pancreas cancer * Patient on an immunosuppressive systemic treatment, such as steroids, in the past 2 years. * Other cancer diagnosis requiring treatment within two years * History of allergic reactions related to the drugs (Nivolumab, Cyclophosphamide, GM-hetastarch, corn, dimethyl sulfoxide, fetal bovine serum, trypsin (porcine origin), yeast or any other component of the GVAX vaccine) in this study. * Patients receiving growth factors within the last 14 days. * Currently have or have history of certain study-specified heart, liver, kidney, lung, neurological, psychological, immune or other medical conditions. * Pregnant or breastfeeding. * Have known history of infection with HIV, hepatitis B, or hepatitis C. * Unwilling or unable to follow the study schedule for any reason. * Presence of tissue or organ allograft, regardless of need for immunosuppression (including corneal allograft) * Squamous pancreatic cancer or adenosquamous pancreatic cancer with malignant squamous cells \>30%