CD274 and neoplasm: The specific microenvironment created by tumor-releasing factors, LPS and hypoxic conditions can induce the expression of PD-L1 in MDSCs.539,540 The immunosuppressive effects of MDSCs on T cells activated by anti-CD3 and anti-CD28 are mediated through the binding of PD-1 on T cells and PD-L1 on MDSCs, leading to T cell inhibition.