CD4 and neoplasm: In addition, immunofluorescence staining of the rechallenged tumors on the 14th day following inoculation compared to the normal mice showed significantly increased infiltrations of both CD8+ T cells and CD4+ T cells (Figure 7G,K), which play critical roles in tumor immune surveillance and long‐term immune memory.[36] After “APHP‐CCCA+808+660” treatment, both CD8+ and CD4+ T cells proliferate and differentiate into memory T cells specific for tumor antigens.