Tumor cells can secrete exosomes carrying PD-L1, inhibit the activation of CD8+T-cells in tumor microenvironment or peripheral circulation, inhibit the proliferation of CD4+T-cells, upregulate the immunosuppressive function of Treg cells, downregulate the expression level of NKG2D in NK cells to inhibit immune killing, and finally promote immune evasion (Chen et al., 2018). This evidence concerns the gene CD274 and neoplasm.