Studies have reported that PD‐L1 expression in adenocarcinoma was higher compared with squamous cell carcinoma in tissue.12, 36, 37, 38, 39, 40 Thus, this study further confirmed that IFN‐γ is one of the most important cytokines for PD‐L1 expression in lung cancer. This evidence concerns the gene IFNG and adenocarcinoma.