CD4 and neoplasm: Besides, liposomal nanoparticle-delivered cGAMP (cGAMP-NP) could directly activate STING of macrophages, repolarize tumor-promoting M2-type macrophages into M1-type macrophages, enhance MHC class molecules, or co-stimulatory molecules, and then induce the differentiation of CD4+ and CD8+ T cells to produce intense anti-tumor responses (48).