CD4 and head and neck squamous cell carcinoma: Differences in tumor-infiltrating immune cells were observed in head and neck squamous cell carcinomas (HNSCC), with a higher frequency of intratumoral B cells present in HPV+ HNSCC and a higher frequency of dysfunctional CD8+ T cells in HPV-HNSCC, while CD4+ Treg suppresses the antitumor immune responses in TME in both HPV+ and HPV.