Although tumor PD‐L1 expression is a potential predictive marker of clinical response to anti‐PD‐1/PD‐L1 therapy, little is known about its association with clinicopathological features, including prognosis, in high‐grade neuroendocrine tumors (HGNETs), including small‐cell lung carcinoma (SCLC) and large‐cell neuroendocrine carcinoma (LCNEC), of the lung. This evidence concerns the gene PDCD1 and neoplasm.