IDO1 and endometrial cancer: DC, dendritic cells; EC, endometrial cancer; FGFR, fibroblast growth factor receptor; FRα, folate receptor α; HER2, Human Epidermal Receptor-2; IDO1, Indoleamine 2,3-dioxygenase; MDSC, myeloid-derived suppressor cells; ORR, overall response rate; OS, overall survival; PARPi, Poly(ADP-ribose) polymerase inhibitor; PFS, progression-free survival; TAM, tumor-associated macrophages.