CD8A and head and neck squamous cell carcinoma: The degree of infiltration of CD8+ T cells has been correlated with improved response to anti-PD-1/PD-L1 agents in melanoma [68], results that could be observed for HNSCC in retrospective studies, showing a correlation between treatment response and degree of infiltration with CD8+ T cells, as well as with the ratio of CD8+T cells/Treg [69].