IDO1 and neoplasm: In the survival analysis, peripheral DC2s (P = .038), tumor‐infiltrating DC1/DC2 cell ratios (P = .012), Foxp3 + Tregs (P = .048), and IDO expression (P = .043) were significantly correlated with OS, at T (P < .01), N (P < .01), and TNM (P < .01) stages (Figure 5).