PDCD1 and neoplasm: Moreover, anti-PD-1 treatment significantly decreased PD-L1 level in non-LD tumor but not in LD tumor (two-way ANOVA, LD: P < 0.001, immunotherapy: P = 0.116), while LD tumors had much lower PD-L1 level compared with non-LD tumors with same treatment (P < 0.001; Fig. 5A and F).