To investigate the potential for a mutually exclusive relationship between B7-H4 and PD-L1 expression in patients with HNSCC, the IHC expression of B7-H4 and PD-L1 was examined using TC, IC, and CPS, which are currently used IHC evaluation methods for PD-L1 expression. The gene discussed is CD274; the disease is head and neck squamous cell carcinoma.