Recently, several reports have shown that high serum PD‐L1 level is a prognostic factor for poor overall survival in patients with gastric cancer,5, 6, 7 hepatocellular carcinoma,8 and biliary tract cancer.9 Akutsu et al reported the clinicopathological significance of serum PD‐L1 levels in esophageal cancer patients.10 However, their report included only 26 surgically treated cases, other cases were 20 endoscopic submucosal dissection treated cases, and 39 nonsurgical treated cases. This evidence concerns the gene CD274 and biliary tract cancer.