Clinical trials show that patients with HNSCC can benefit from programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) therapy (one type of ICI) and obtain a better quality of life (Leemans et al., 2018; Cramer et al., 2019). The gene discussed is PDCD1; the disease is head and neck squamous cell carcinoma.