The FDA approved the application of several immune checkpoint inhibitors, such as anti-PD-1 or programmed cell death 1-ligand 1 (PD-L1) antibodies, which include nivolumab and pembrolizumab, durvalumab and atezolizumab for treating the recurrence/metastasis of HNSCC [44]. The gene discussed is PDCD1; the disease is head and neck squamous cell carcinoma.