A Single-arm, Multicenter, Exploratory Study of Adebrelimab Combined With Apatinib and Systemic Chemotherapy for Initially Unresectable Biliary Tract Cancer

Inclusion Criteria: \- 1. Pathological or histological diagnosis of malignant tumor of the biliary tract; 2. Patients who are classified as TxNx and TxNxM1 according to the UICC/AJCC TNM staging system (9th edition, 2024), and who, based on the judgment of the research team, meet the criteria for newly diagnosed incurable cases or are not suitable for surgery; 3. Age: 18-80 years old; 4. Expected survival period \> 3 months; 5. Both genders are eligible; 6. ECOG PS score of 0 or 1; 7. No severe complications, such as hypertension, coronary heart disease, and history of mental illness, no severe allergy history; non-pregnant and non-lactating; 8. The patient's organ and hematological system functions meet the following requirements: 1. Absolute neutrophil count (ANC) ≥ 1.5 × 10\^9/L; 2. Platelet count ≥ 75 × 10\^9/L; 3. Hemoglobin ≥ 90 g/L; 4. Serum total bilirubin ≤ 1.5 x upper limit of normal (ULN); 5. Aspartate aminotransferase (AST) and alanine aminotransferase ≤ 2.5 x ULN; 6. Albumin ≥ 3 g/dL 7. Creatinine ≤ 1.5 x ULN 9. Patients can understand and sign the informed consent form to participate in the trial study; good compliance. 10\. Newly diagnosed patients, who have not undergone any local or systemic treatment for the tumor in the past and have undergone radical resection surgery for biliary cancer, and whose disease recurs 2 years after the surgery can be included; 11. Patients with potential fertility should use a medically approved contraceptive method (such as intrauterine device, contraceptive pills, or condoms) during the study treatment and within 1 month after the end of the study treatment; and the serum or urine HCG test must be negative within 72 hours before the study enrollment, and must be non-lactating. Exclusion Criteria: * 1\. Patients who received immune checkpoint inhibitors before enrollment, or those who directly received another stimulatory or co-inhibitory T-cell receptor (such as CTLA-4, CD137); 2. Patients who used any other investigational drug within 4 weeks before enrollment; 3. Patients with any active autoimmune disease or history of autoimmune disease (such as interstitial pneumonia, uveitis, enteritis, hepatitis, pituitary inflammation, vasculitis, myocarditis, nephritis, hyperthyroidism, hypothyroidism after hormone replacement therapy); children with asthma who have completely recovered after adulthood and do not require any intervention can be included, but patients requiring bronchodilator drug intervention cannot be included; 4. Congenital or acquired immune deficiencies, such as infection with human immunodeficiency virus (HIV), active hepatitis B (HBV DNA \> 500 IU/ml), hepatitis C (positive hepatitis C antibody, HCV-RNA above the detection limit of the analytical method), or co-infection of hepatitis B and hepatitis C; 5. Serious infections occurred within 4 weeks before the first administration (such as intravenous infusion of antibiotics, antifungal or antiviral drugs), or unexplained fever \> 38.5°C during screening or before the first administration; 6. History of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation; 7. Having an uncontrolled mental disorder; 8. Concurrently having severe and/or uncontrollable diseases that may affect the participation in the study, such as unstable angina pectoris, myocardial infarction within 6 months, unstable symptomatic arrhythmia, symptomatic congestive heart failure, poorly controlled diabetes, excessive activity, uncontrollable infection after insufficient biliary drainage (such as tumor blocking the bile duct); 9. Other cancers that occurred in the past (within the past 5 years) or simultaneously, excluding non-melanoma skin cancer and carcinoma in situ; 10. History of allergy or hypersensitivity to any study drug or any monoclonal antibody; 11. Unable or unwilling to sign the informed consent form.