IBI310 in Combination With Sintilimab in Patients With Advanced Biliary Tract Cancer

Inclusion Criteria: 1. The subject must sign the written informed consent form, and can comply with the visits and related procedures specified in the protocol. 2. Aged ≥18 years. 3. Patients with unresectable or relapsed or metastatic advanced Biliary tract cancer,and diagnosed by histology/cytology (except carcinoma of ampulla). 4. Had progressed after receiving at least first-line systemic treatment (if a patient has progressed within 6 months after receiving systemic treatment during adjuvant chemotherapy or concurrent radiochemotherapy, she will be deemed to have received first-line treatment). 5. Patients who have never received any anti-PD-1, anti-PD-L1/L2 antibody, anti-CTLA-4 antibody, or other immunotherapy. 6. The subject must have at least one measurable lesion as the target lesion (according to RECIST V1.1). A measurable lesion in the radiation field from previous radiotherapy or local treatment, can also be chosen as the target lesion if confirmed progression. Exclusion Criteria: 1. Diagnosis of other malignant tumors within 5 years before the first administration, excluding radically cured skin basal cell carcinoma, skin squamous cell carcinoma, radically resected carcinoma in situ and/or thyroid papillary carcinoma. 2. Patients who have previously received organ or bone marrow transplantation. 3. Patients with acute or chronic active hepatitis B or C infection, hepatitis B virus (HBV) DNA\> 2000 IU/ml or 104 copies/ml; hepatitis C virus (HCV) antibody positive and HCV-RNA \>103 copies/ml;. Patients with acute or chronic active hepatitis B or C infection who have received nucleotide antiviral therapy and are below the above standards can be selected. 4. Uncontrollable hypertension, systolic blood pressure ≥150 mmHg or diastolic blood pressure ≥100 mmHg after best medical treatment, history of hypertensive crisis or hypertensive encephalopathy. 5. Pleural effusion, ascites, and pericardial effusion with clinical symptoms or requiring drainage , patients who only shows with a few pleural effusion, ascites, and pericardial effusion by imaging and with no clinical symptoms can be selected.