CD274 and head and neck squamous cell carcinoma: Furthermore, the distinct immunogenomic profiles of higher- and lower-risk tumors — the latter of which are more often characterized by high CD8-positive T cell infiltration, a CPS of 1 or higher, a high TMB, an APOBEC signature, viral positivity, a weaker smoking signature, and a genetically intact PD-L1 pathway — seemingly confirm the collective importance of these factors to ICB response in HNSCC.