In order to find the genes that are most critical to the TME in HNSCC, we combined the genes located in the middle node of the PPI network (Figure 3A) and the p-value less than 0.05 in the survival analysis to screen out four genes CCR5, CD3E, CD4, and HLA-DRB1. The gene discussed is HLA-DRB1; the disease is head and neck squamous cell carcinoma.