A Phase II/III, Multicenter, Randomized, Placebo-controlled Study of Gemcitabine Plus Cisplatin With or Without Bintrafusp Alfa (M7824) as First-line Treatment of Biliary Tract Cancer

• 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