CD274 and neoplasm: One way is to exhaust tumor reactive T cells to impair their anti-tumor function, like expressing immune checkpoint molecules (such as PD-L1) to induce tumor reactive T cells apoptosis or exhaustion by activating immunosuppressive pathways (12), or recruiting immunosuppressive cells such as tumor associated macrophages (TAM), tumor associated fibroblasts (CAF), regulatory T cells (Tregs) and myelogenous suppressor cells (MDSCs) to suppress the activity of cytotoxic T lymphocytes (CTLs) (13, 14).