CD8A and head and neck squamous cell carcinoma: Patients with HNSCC in the high-risk group contained lower infiltration levels of memory B cells (p < 0.05), CD8+ T cells (p < 0.001), follicular helper T cells (p < 0.001), regulatory T cells (Tregs) (p < 0.001), and activated mast cells (p < 0.001) while having higher infiltration levels of resting NK cells (p < 0.01), M0 macrophages (p < 0.01), M2 macrophages (p < 0.05), and resting mast cells (p < 0.001) than did those in the low-risk group.