Combination of Anti-PD-1 Antibody and Chemotherapy for Unresectable Intrahepatic Cholangiocarcinoma

Inclusion Criteria: * Has histologically confirmed diagnosis of advanced (metastatic) and/or unresectable (locally advanced) biliary tract cancer (intra-or extrahepatic cholangiocarcinoma) * Has at least one measurable, evaluable lesions based on Response Evaluation Criteria in Solid Tumors (RECIST 1.1), as determined by the research center investigator * Participants with a history of hepatitis B or hepatitis C can be enrolled if they meet study criteria * Is willing to provide archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion * Has a life expectancy of greater than 3 months * Has adequate organ function * Has EOCG score 0 or 1 * Has willing to voluntarily participate in clinical trial and sign informed consent Exclusion Criteria: * Histology includes fibrolamellar, hepatocytes, sarcomatoid liver cancer, hepatocytes, hepatocellular carcinoma and other components. Or has had previous biliary tract cancer (intra-or extra hepatic cholangiocarcinoma) or combined with other cancer with an exception of basal cell carcinoma and squamous cell carcinoma of the skin carcinoma in situ that has been radical treated. * Has active tuberculosis and were receiving anti-tb treatment, or receiving anti-tb treatment within a year before were randomly assigned. * Has symptomatic or poorly controlled circulatory disease, such as Congestive heart failure(NYHA III-IV), arrhythmia instability, type I angina, coronary heart disease, etc * Has esophageal and gastric varices bleeding due to portal hypertension, or with history of inflammatory bowel disease, gastrointestinal perforation and intestinal obstruction, abdominal abscess, or chronic diarrhea. * Has life-threatening bleeding or venous thromboembolism events occurred in the first six months before enrollment, or the patient was prone to severe bleeding or coagulation dysfunction, or was undergoing thrombolytic therapy * Has active autoimmune disease requiring systemic treatment within the two years before enrollment , especially those with immunosuppressive drugs, who were unable to control or who needed large amounts of immunosuppressive drugs to control the disease, excluding topical glucose-corticosteroids or systemic use, and prednisone less than 10 milligrams per day * Has central nervous system disease with symptoms, such as primary brain tumor, stroke, epilepsy, etc. Patients who have undergone central nervous system or known brain metastases * Has acute or severe hepatitis infection, or a severe bacterial or bacterial infection in an active or clinically poorly controlled, or with congenital or acquired immune deficiency such human immunodeficiency virus (HIV) infected * Has previous allogeneic stem cell or parenchymal organ transplantation, including after liver transplantation * Has history of allergies to drugs involved in this study * Women who are pregnant or lactating, or who do not want to use contraception during the trial.