HPV+ HNSCC tissues had more lymphocytes and higher levels of PD-L1 than HPV- HNSCC tissues, and the infiltrated CTLs expressed more PD-1.22 PD-L1 can deliver additional immunosuppressive signals by binding to the CD80 receptor, which is expressed on T cells. This evidence concerns the gene PDCD1 and head and neck squamous cell carcinoma.