CD274 and cancer: Evasion of immune destruction is a major hallmark of cancer [31], and tumors use a variety of immunosuppressive mechanisms including loss of neoantigen expression; downregulation of antigen presentation; recruitment of immunosuppressive immune cells such as regulatory T cells [32,33], myeloid-derived suppressor cells (MDSCs), and CD71+ erythroid cells [34,35]; and upregulation or secretion of immune-modulatory molecules such as anti-inflammatory cytokines and inhibitory checkpoint proteins (e.g., PD-L1) to accomplish this feat [36].