CD274 and gastric cancer: The exosomes secreted by M1 macrophages of human peripheral blood mononuclear cells (PBMC) induced by lipopolysaccharide (LPS) and IFN-γ carrying miRNA-16-5p can specifically target and downregulate PD-L1 expression in gastric cancer cells, block the PD1/PDL1 checkpoint, reduce the immune escape of gastric cancer cells monitored by T cells, and activate T cell-dependent immune responses that inhibit tumor development in vitro and in vivo (Li et al., 2020).