Immune checkpoint inhibitor therapy utilizing monoclonal antibodies directed against programmed cell death-1 (PD-1) and its ligand 1 (PD-L1) to target tumor-specific immune tolerance has become an established treatment modality for head and neck cancer patients with recurrent or metastatic HNSCC [14,15]. The gene discussed is PDCD1; the disease is head and neck squamous cell carcinoma.