 Ways include chemokine CCL2 nitration, which traps T cells in the stroma.Tumor vasculature helps tumors preferentially recruit other immune cells over T cells, in part through endothelial cell (EC)–specific expression of FasL, ETBR, and B7H3.Myelomonocytic and tumor cells can up-regulate expression of PD-L1, partly driven by hypoxic conditions and cytokine production, such as IFNβ.