The purpose of this study is to assess the safety and efficacy of Gemcitabine/cisplatin combined with Adebrelimab and Mecapegfilgrastim in neoadjuvant treatment of potentially resectable Biliary Tract Neoplasms.

After being informed about the study and potential risks, patients giving written informed consent will undergo a 1-week screening period to determine eligibility for study entry. At week 0, patients who meet the eligibility requirements will be receive Gemcitabine/cisplatin combined with Adebrelimab and Mecapegfilgrastim three weeks a cycle, surgery was performed after 4 cycles.

Inclusion Criteria:

• Male or female
• Age ≥ 18 years，≤ 75 years
• Patients with untreated resectable locally advanced biliary tract cancer (BTC) who are difficult to directly resecte surgically
• Ability to provide written informed consent prior to participation in any study-related procedure
• Eastern Cooperative Oncology Group (ECOG) performance status 0-1
• At least one, not previously irradiated, measurable lesion according to RECIST (version 1.1).
• Adequate organ function

Exclusion Criteria:

• Diagnosis of mixed ampullary, hepatocellular, and cholangiocarcinoma
• Known history of a serious allergy to any monoclonal antibody
• Any active malignancy prior to the start of treatment
• Active or history of autoimmune disease
• Other acute or chronic conditions, psychiatric disorders, or laboratory abnormalities that may increase the risk of study participation
• Pregnant or lactating women