CD4 and head and neck squamous cell carcinoma: Through the analysis of gene expression and prognosis of HNSCC patients in GEO, Oncolnc, Kaplan-Meier plotter, TIMER and other databases, it was found that YTHDC2 could be an independent tumor suppressor gene to judge the prognosis of HNSCC, and the expression level of YTHDC2 was positively correlated with the infiltration level of CD4+T cell subsets.