CD274 and melanoma: Moreover, the TME also contains different subsets of inhibitory immune cells, including Treg, myeloid-derived suppressor cells and tumor-associated macrophages, that can be activated after RT (71–78) Furthermore, it was shown that RT can increase the expression of PD-L1 on melanoma and glioblastoma cells thereby hampering effecting killing of the tumor cells by cytotoxic T lymphocytes (79).