The PD‐L1 expression was not associated with clinical parameters such as age, gender, smoking status, and stage, but it was associated with tumor histology, indicating that positive PD‐L1 was expressed more frequently in adenocarcinoma than in squamous cell carcinoma (63.8% vs. 45.3, P = 0.042; Table S1). This evidence concerns the gene CD274 and adenocarcinoma.