CD4 and cancer: In accordance with this observation, the accumulating evidence of the promoted immunosurveillance indicates that (i) cancers infiltrated with more positive immune effectors (such as CD8+ and CD4+ CTLs, NK cells, and activated DCs) and relatively fewer immunosuppressive cells (such as FOXP3+ Tregs and myeloid-derived suppressor cells) exhibit a favorable prognosis [12, 54, 55]; (ii) anti-cancer therapy (such as ICD inducers) is particularly efficient if local anti-cancer immunity is activated [12, 56].