In our research, 12 ICC patients from a phase 2 clinical trial (ChiCTR2000036652), aiming to evaluate the efficacy and safety of sintilimab (a kind of anti-PD-1 antibody) plus GemCis as first-line treatment in advanced BTC patients, were enrolled as the exploratory cohort. This evidence concerns the gene PDCD1 and intrahepatic cholangiocarcinoma.