In addition, different cholangiocarcinoma patient population in each study may contribute to the discrepancy since PD-L1 is highly expressed on special subtypes of cholangiocarcinomas such as intrahepatic lymphoepithelioma like cholangiocarcinoma [17], occupational cholangiocarcinoma [18] and liver fluke related cholangiocarcinoma [19] compared with conventional cholangiocarcinoma. Here, CD274 is linked to cholangiocarcinoma.