Durvalumab Combined With S-1 as Adjuvant Therapy of Resectable BTC

Inclusion Criteria: 1. Age ≥ 18 years, both males and females are eligible. 2. Intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gallbladder cancer(Histologically confirmed). 3. TNM stage before surgery: GBC/DCC T2-T4, N+, M0; ICC T1b-T4, N+, M0; PCC, any T, any N, M0 (according to UICC/AJCC TNM staging (8th edition)) . 4. Patients must undergo radical resection, including liver resection or pancreatectomy, before enrollment. 5. Time between surgery and enrollment \< 12 weeks. 6. R0 resection. 7. ECOG PS 0-1. 8. No distant metastasis confirmed by MRI. 9. Adequate organ and marrow function, as defined below. Haemoglobin ≥ 9 g/dL Absolute neutrophil count ≥ 1.5 × 109/L Platelet count ≥ 100 × 109/L Serum bilirubin ≤ 1.0 × ULN ALT and AST ≤ 2.5 × ULN Calculated creatinine clearance \> 50 mL/minute as determined by Cockcroft-Gault (using actual body weight) or 24-hour urine creatinine clearance. Exclusion Criteria: 1. Patient diagnosed with Ampulla of Vater(AoV). 2. Time between surgery and enrollment \>12 weeks. 3. Receive anti-tumor treatment before surgery, including chemotherapy, radiotherapy, targeted therapy, immunotherapy, local therapy, etc. 4. The tumor was not completely removed, or the postoperative pathology indicated that it was not a biliary tract tumor. 5. Receive other anti-tumor treatments, such as chemotherapy, radiotherapy, or other research drugs, during postoperative adjuvant therapy. 6. Severe infection within 4 weeks before enrollment. 7. Participated in another interventional clinical study. 8. Other factors deemed by the investigator to make the participant unsuitable for participation in this study.