IDO1 and neoplasm: Our findings indicated a significantly (p < 0.05) higher expression of protein biomarkers associated with the presence and activity of immune cells, including CD45, CD3, CD68, CD163, CD11c, CD8, HLA-DR, CD40, PD-L1, and IDO1, in the tumor compartments of patients with CR compared to those with PD (Fig. 2C).