RecruitingPhase 1Drug trialA Study of Adebrelimab in Combination With Apatinib Gemcitabine and Cisplatin in Biliary Tract MalignanciesEvaluating the efficacy and safety of adebrelimab in combination with apatinib, gemcitabine and cisplatin in the neoadjuvant treatment of patients with biliary tract malignancies.