PDCD1 and neoplasm: The results showed that EL4 tumor-bearing mice treated with anti-PD-1 (n = 8) or the combined therapy (GM-CSF combined with PD-1 antibody, n = 8) had longer survival (Fig. 1A) and significant delay in tumor growth (Fig. 1B-D) compared with the mice in control group (n = 8) or mice treated with GM-CSF alone (n = 8).