Inclusion Criteria:  Age ≥ 19 years old Capable of understanding and complying with the protocol requirements and signed informed consent The patients were confirmed as bilary tract cancer (gall bladder cancer, extrahepatic cholangiocarcinoma, intrahepatic cholangiocarcinoma) by histopathology or cytology Patients with inoperable or metastatic or recurrent biliary tract cancer Patients who underwent in-house next-generation sequencing Patients planning to receive Gemcitabine, Cisplatin, nab-paclitaxel triplet chemotherapy At least one measurable objective lesion was identified based on the RECIST 1.1 criteria Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. The expected survival a ≥3 months  Exclusion Criteria:  The subject has uncontrolled, significant intercurrent or recent illness including infection for organ failure Prior palliative chemotherapy for biliary tract cancer Dementia, altered mental state, or any mental illness that prevents understanding or informed consent Other conditions that researchers not think to be suitable for enrollment.