Besides PD-1, the expression of PD-L1 (B7-H1, CD274)/L2 (B7-DC, CD273) is detected in TAMs, which induce CD8+ T cells anergy and apoptosis through PD-1 binding on the surface of CD8+ T cells to inhibit anti-tumor immune response (Figure 2C). The gene discussed is PDCD1; the disease is neoplasm.