In contrast, M2-like cells not only produce tumor growth factors such as IL-6 but also produce angiogenic molecules, including VEGF and immunosuppressive factors such as arginase 1 (Arg1), IL-10, TGF-β, and indoleamine 2,3-dioxygenase (IDO), resulting in tumor promotion [95]. Here, IDO1 is linked to neoplasm.