CD8A and head and neck squamous cell carcinoma: InFig. 2, we focused on TILs and found that4-1BBexpression had a significant partial correlation with lymphocytes infiltration in HNSCC, including B cells (correlation = 0.391;p = 8.30e-19), CD8+ T cells (correlation = 0.509;p = 1.42e-32), and CD4+ T cells (correlation = 0.654;p = 6.59 e-60;Fig. 2).