GemCis Plus PD-1/PD-L1 Inhibitor in Advanced Biliary Tract Cancer: Efficacy and Immune Microenvironment （BTC-IM-1）

"Gemcitabine: 1000 mg/m², intravenous infusion, on Day 1 and Day 8 Cisplatin: 25 mg/m², intravenous infusion, on Day 1 and Day 8 PD-1/PD-L1 inhibitor: An approved agent (e.g., Pembrolizumab, Nivolumab, Atezolizumab, etc.) will be selected based on clinical practice and administered at standard doses and schedules.~Each treatment cycle lasts 21 days, continuing until disease progression, unacceptable toxicity, or patient/physician decision to discontinue."