IDO1 and neoplasm: Compared with SVCT (SVC tumor), tumor growth was attenuated in VPCT (VPC tumor), STCT (STC tumor), TPCT (TPC tumor), and IFCT (IFC tumor) (Figure 6M); IDO1 expression was significantly reduced (Figure 6N), relative Trp content was high (Figure 6O), the relative [Kyn]/[Trp] ratio was low (Figure 6P), and CD8+T proportion was upregulated (Figure 6Q).