In this context, it may be of importance that HPV+ HNSCCs contain a distinct population of PD-1 high expressing CD8 pos T cells [14], while the frequency of myeloid derived suppressor cells and tumor activated macrophages seems to be independent of HPV infection status in HNSCC [23]; an observation that could be reproduced in the present dataset. This evidence concerns the gene PDCD1 and head and neck squamous cell carcinoma.