The neutrophil-to-lymphocyte ratio (NLR) has also gained attention as a potential predictive biomarker for immunotherapy efficacy, as it may correlate with treatment outcomes.<h4>Objective</h4>To examine the expression of PD-L1 on TIICs and assess the influence of PD-L1 and NLR on immunotherapy outcomes following biliary tract cancers (BTC) recurrence.<h4>Methods</h4>From January 1, 2017, to January 1, 2020, this study enrolled 239 patients from the Department of Pancreaticobiliary Surgery at Sun Yat-sen University Cancer Center. The gene discussed is CD274; the disease is biliary tract neoplasm.