RecruitingPhase 2Drug trialAdebrelimab Combined with Apatinib and Gemcitabine and Cisplatin (GP) First-line Treatment for Unresectable Biliary Tract CarcinomaThis study is designed to combine anti-angiogenic drugs on the basis of PD-L1+ gemcitabine/cisplatin, hoping to further improve the curative effect of advanced BTC treatment and provide more choices for first-line treatment of BTC in China.