This study is a prospective, observational study designed to analyze the safety, tolerability, and efficacy of first-line treatment using the combination of gemcitabine and cisplatin plus anti-PD-1/PD-L1 antibodies for patients with advanced cholangiocarcinoma.

This is a prospective cohort study of combination anti-PD-1/PD-L1 antibodies plus Gemcitabine and Cisplatin chemotherapy for adult patients (≥18) with advanced cholangiocarcinoma

Gemcitabine and Cisplatin (GC): This chemotherapy doublet has been the historical standard of care for advanced cholangiocarcinoma. It works by interfering with DNA synthesis and causing DNA cross-linking, leading to tumor cell apoptosis.

Anti-PD-1/PD-L1 antibodies: Immunotherapy (including pembrolizumab, durvalumab, envafolimab, tislelizumab, etc.) is designed to block the PD-1/PD-L1 immune checkpoint pathway, thereby reinvigorating T-cells to recognize and attack tumor cells. Recent pivotal trials (e.g., TOPAZ-1, KEYNOTE-966) have demonstrated that adding immunotherapy to GC chemotherapy significantly improves overall survival compared to chemotherapy alone.

This study aims to evaluate the real-world safety, tolerability, and clinical efficacy of this combination regimen in specific clinical practice settings for unresectable late-stage cholangiocarcinoma patients.

Inclusion Criteria:

• 1. ≥18 years old, male or female 2. Histologically or cytologically confirmed locally advanced or metastatic biliary tract cancer (including ICC, ECC, or GBC) that is not amenable to curative surgery or local therapies.

  3. Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1 4. Patient has given written informed consent. 5. The function of important organs meets the requirements 6. Expected survival ≥12 weeks 7. Non-surgical sterilization or women of childbearing age need to use a medically-accepted contraceptive (such as an intrauterine device, contraceptive or condom) during the study period and within 3 months after the end of the study treatment period.

Exclusion Criteria:

• 1. The patient has any active autoimmune disease or a history of autoimmune disease (such as the following, but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, pituitary inflammation, vasculitis, nephritis, thyroid Hyperfunction; patients with vitiligo; complete remission of asthma in childhood, can be included without any intervention after adulthood; asthma patients who require bronchodilators for medical intervention cannot be included); 2. The patient is using immunosuppressive agents or systemic hormonal therapy to achieve immunosuppressive purposes (agents amount > 10 mg / day of prednisone or other therapeutic hormones), and continue to use within 2 weeks before enrollment; 3. Have clinical symptoms or disease that are not well controlled; 4. Significant clinically significant bleeding symptoms or a clear bleeding tendency within 3 months prior to randomization; 5. Arterial/venous thrombosis in the first 6 months of randomization 6. According to the investigator, the patient has other factors that may affect the results of the study or lead to the termination of the study, such as alcohol abuse, drug abuse, other serious diseases (including mental illness) requiring combined treatment, and serious laboratory abnormalities.#with family or social factors, it will affect the safety of patients. 7. Known hypersensitivity to Gemcitabine, Cisplatin, or platinum-containing compounds; significant hearing impairment (grade ≥2) or peripheral neuropathy (grade ≥2) that contraindicates Cisplatin;

Patients with locally advanced or metastatic biliary tract cancer diagnosed histologically or cytologically.