INCMGA00012 in Patients With Previously Treated Unresectable or Metastatic Adenosquamous Pancreatic or Ampullary Cancer

Inclusion Criteria: * Age ≥18 years. * Have histologically or cytologically - proven adenosquamous carcinoma of the pancreas or ampulla. * Has unresectable or metastatic measurable disease. * Has received (or been intolerant to or ineligible for) at least 1 prior line of cytotoxic chemotherapy and received no more than 2 prior systemic treatments. * Presence of at least one lesion with measurable disease. * Accept to have a tumor biopsy of an accessible lesion at baseline and on treatment. * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. * If HIV-positive, then all of the following criteria must also be met: cluster of differentiation (CD) 4+ count ≥ 350/μL, undetectable viral load, and receiving highly active antiretroviral therapy. * Life expectancy of greater than 3 months. * Patients must have adequate organ and marrow function defined by study-specified laboratory tests prior to initial study drug. * Woman of childbearing potential must have a negative pregnancy test and follow contraceptive guidelines as defined per protocol. * Men must use acceptable form of birth control while on study. * Ability to understand and willingness to sign a written informed consent document. Exclusion Criteria * Known history or evidence of brain metastases. * Has had chemotherapy, radiation, or biological cancer therapy within 14 days prior to the first dose of study drug. * Has received an investigational agent or used an investigational device within 28 days of …