In 2016, immunotherapy using anti‐programed cell death protein 1 (PD‐1) inhibitors, such as nivolumab or pembrolizumab, was approved by the US Food and Drug Administration for platinum‐refractory recurrent or metastatic (R/M) HNSCC based on the promising results of large‐scale clinical trials (Checkmate‐041, KEYNOTE‐012) [5, 6, 7]. The gene discussed is PDCD1; the disease is head and neck squamous cell carcinoma.