In addition, studies have shown that NKG2D ligands are also expressed in tumor blood vessels, immunosuppressive cells (such as Treg and MDSC), and endothelial cells in the tumor microenvironment, which suggests that NKG2D-CAR T can target some cells in the tumor microenvironment while targeting tumor cells, and can relieve the inhibitory effect of the tumor microenvironment to a certain extent (23). This evidence concerns the gene KLRK1 and neoplasm.