CD274 and neoplasm: PD-1 level in tumor tissues in ENKTL patients [3.50(0.00–9.75)] was significantly lower than in DLBCL patients [21.00(1.75–44.00), P = 0.0021] (Fig. 2C), while PD-L1 level was not statistically different between ENKTL [49.50(35.25–80.00)] and DLBCL [50.50(2.50–77.00)] groups (Fig. 2D).