CD274 and neoplasm: Key barriers include the immunosuppressive tumor microenvironment (TME), which impedes T-cell infiltration and function through mechanisms such as immunosuppressive cytokine secretion (TGF-β, IL-10) and PD-L1 expression (9–11), and the frequent lack of ideal, homogeneously expressed tumor-specific antigens, increasing the risk of on-target, off-tumor toxicity.