The results showed that the expression of YTHDC2 was significantly correlated with tumor purity (r =  − 0.145, P = 1.29e−03), B cell (r = 0.098, P = 3.26e−02), CD8+ T cells (r = 0.191, P = 2.72e−05), CD4+ T cells (r = 0.21, P = 3.50e−06), neutrophils (r = 0.241, P = 9.46e−08) and dendritic cells (r = 0.216, P = 1.65e−06) in HNSCC (Figs. 5A–5G). The gene discussed is CD4; the disease is neoplasm.