HNSCC can modulate the immune response to favor induction and conversion to immunosuppressive cells such as Tregs, which are abundant in the tumor microenvironment (TME) as well as peripheral blood, exerting their immunosuppressive function by inducing apoptosis of CD8+ T cells and inhibiting proliferation of CD4+ T cells (15–17). Here, CD8A is linked to head and neck squamous cell carcinoma.