INCMGA00012 Plus Chemotherapy in Participants With Advanced Solid Tumors (POD1UM-105)

Inclusion Criteria: * Advanced and/or metastatic solid tumors including the following: histologically or cytologically confirmed diagnosis of Stage IIIB not amenable to curative treatment or Stage IV non-small cell lung cancer (pemetrexed-platinum treatment groups must have nonsquamous histology type); and histologically or cytologically confirmed diagnosis of advanced/metastatic unresectable malignant pleural mesothelioma. * No prior systemic treatment with the following exceptions: participants with a known sensitizing mutation (eg, BRAF, EGFR, ALK, or ROS1) should have had disease progression on or following an approved targeted tyrosine kinase inhibitor; and participants who received adjuvant or neoadjuvant chemotherapy are eligible if the adjuvant/neoadjuvant therapy was completed at least 6 months before the date of enrollment. * Measurable or nonmeasurable tumor lesions per RECIST v1.1. * Eastern Cooperative Oncology Group performance status 0 to 1. Exclusion Criteria: * Received prior treatment with checkpoint inhibitor agents (such as anti-PD-1, anti-PD-L1, anti-PD-L2, or anti-CTLA-4). * Had major surgery within 3 weeks before the first dose of study treatment. * Received radiation therapy to the lung(s) that is \> 30 Gy within 6 months of the first dose of study treatment. * Received palliative radiotherapy within 7 days before the first dose of study treatment. * Has ≥ Grade 2 residual toxicities from the most recent prior therapy (except alopecia). * Organ function (renal, hepatic), bone marrow reserve, and coagulation panel outside the protocol-defined laboratory values. * Is currently participating and receiving investigational therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 4 weeks before the first dose of study treatment. * Has active autoimmune disease requiring systemic immunosuppression with corticosteroids (\> 10 mg once daily of prednisone or equivalent) or immunosuppressive drugs within 2 years before the first dose of study treatment. * Is on chronic systemic steroids (\> 10 mg once daily of prednisone or equivalent). * Known active central nervous system metastases and/or carcinomatous meningitis (patients with previously-treated and clinically stable brain metastases are eligible and a washout period of ≥ 4 weeks since radiation therapy is required). * Known additional malignancy that is progressing or requires active treatment. * Evidence of interstitial lung disease or active, noninfectious pneumonitis. * History of organ transplant, including allogeneic stem cell transplantation. * Active infections requiring systemic antibiotics. * Known active hepatitis B or C. * Has a diagnosis of immunodeficiency, including participants known to be HIV positive (positive for HIV 1/2 antibodies). * Significant cardiac event within 6 months before Cycle 1 Day 1. * Has received a live vaccine within 28 days of the planned start of study treatment. * Known hypersensitivity to any component of the study drugs, excipients, or another monoclonal antibody which cannot be controlled with standard measures (eg, antihistamines and corticosteroids).