CD4 and neoplasm: IHC analysis of tumor tissues (Fig. 2F) further confirmed that anti-mPD-1 treatment led to a substantial increase in tumor‐infiltrating lymphocytes (TILs) and cleaved caspase‐3, along with moderate increases in CD4, CD8α, and PD‐1 staining coupled with a decline in F4/80, and PCNA, consistent with western blot findings.