Gemcitabine Plus Cisplatin With or Without Bintrafusp Alfa (M7824) in Participants With 1L BTC

Inclusion Criteria: * Are participants with histologically or cytologically confirmed locally advanced or metastatic BTC * Participants must have available tumor tissue (primary or metastatic) (archival or fresh biopsies) before the first administration of study treatment * At least 1 measurable lesion according to RECIST 1.1 * Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1 at study entry and at Week 1, Day 1 prior to dosing * Life expectancy of \>= 12 weeks, as judged by the Investigator * Adequate hematological function, hepatic function, renal function, coagulation function as defined in the protocol * Hepatitis B virus (HBV) deoxyribonucleic acid (DNA) positive participants must be treated and on a stable dose of antivirals * Other protocol defined inclusion criteria could apply Exclusion Criteria: * Previous and/or intercurrent cancers * Receipt of any organ transplantation, including allogeneic stem-cell transplantation, but with the exception of transplants that do not require immunosuppression * Participants with symptomatic central nervous system (CNS) metastases * Significant acute or chronic infection including known history of positive test for human immunodeficiency virus (HIV), active tuberculosis, uncontrolled biliary infection and active bacterial or fungal infection requiring systemic therapy (with the exception of hepatitis B and hepatitis C) requiring systemic therapy at study entry and at Week 1 Day 1 prior to dosing. * Active…