CD8A and head and neck squamous cell carcinoma: To explore the mechanism of antitumor activity of anti‐TIM3 therapy, we investigated the CD4+ T cells, CD8+ T cells, TIM3+CD4+ cells, and TIM3+CD8+ cells in both tumor microenvironment and peripheral environment, including spleen, draining LN, and blood of HNSCC mice as shown by representative pictures (Fig. 6A,B).