With the induction by cytokines such as IFN-γ and hypoxic tumor microenvironment, PD-L1 has been found on both tumor cells and host inflammatory cells such as myeloid derived DCs (Curiel et al., 2003; Dong et al., 2002), tumor-infiltrating myeloid derived suppressor cells (Noman et al., 2014). This evidence concerns the gene CD274 and neoplasm.