explored several HNSCC cell lines and found that the programmed death ligand-1 (PD-L1), which limits the function of activated T lymphocytes when they interact with the ICP receptor programmed death-1 (PD-1), is expressed by tumor cells in an EGFR- and JAK2/STAT1-dependent manner (159). This evidence concerns the gene STAT1 and head and neck squamous cell carcinoma.