Hence, we investigated the expression of the known immune-modulatory proteins OX40, programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) in SCCHN on different T-cell subsets of tumor-infiltrating lymphocytes (TIL) to ascertain whether these proteins could potentially be targeted alone or in combination for future clinical trials. This evidence concerns the gene CTLA4 and head and neck squamous cell carcinoma.