We previously reported that both PD-L1-CPS-negative expression and a low CD8+ TIL infiltration were significantly associated with a poorer disease-specific survival (DSS) and overall survival (OS) in this HNSCC patient cohort (Supplementary Figure S1), but on multivariate analysis, only CD8+ TIL infiltration was independently associated with survival [12]. Here, CD274 is linked to head and neck squamous cell carcinoma.