Recently, studies have revealed that these immunosuppressive macrophages in the PMN can be characterized by the expression of triggering receptor expressed on myeloid cells 2 (TREM2) and programmed death-ligand 1 (PD-L1).14,15 Under certain conditions, the high expression of PD-L1 in macrophages can promote regulatory T (Treg) cell differentiation,16,17 which are critical mediators of immune tolerance and can suppress anti-tumor immune responses. Here, CD274 is linked to neoplasm.