The immune checkpoint inhibitor anti-programmed cell death protein 1 (PD-1)/PD-L1 was the first drug to demonstrate prognostic benefits for the treatment of R/M (recurrent/metastatic) HNSCC unresponsive to platinum-based treatment, and was recently granted approval for use by the Food and Drug Administration (FDA). The gene discussed is PDCD1; the disease is head and neck squamous cell carcinoma.