CD4 and head and neck squamous cell carcinoma: Based on the optimal cutoff value of the abundance of each immune cell, HNSCC patients were divided into two groups for survival analysis, which indicated that the more abundance of follicular helper T cells, Tregs, activated memory CD4+ T cells, CD8+ T cells, activated B cells, plasma cells, resting dendritic cells and resting mast cells, the better the OS.