IDO1 and cancer: Immunomodulatory CAFs (iCAFs) presented with enhanced expression of the matrix remodelers MMP1 and MMP3, the pro-inflammatory cytokines IL6 and CXCL8 and the immune-suppressive molecule IDO1 among their top ten differentially expressed genes (DEGs), thus suggesting an immunoregulatory and cancer invasion-supportive phenotype (Fig. 3A, B).