IDO1 and cancer: Such conjugates show promising activity against cancer-associated carbonic anhydrase IX (CA IX) [30], hypoxia-inducible factor-1 (HIF-1) [31,32], nicotinamide phosphoribosyltransferase (NAMPT) [33], cyclooxygenase (COX) [34,35], lipoxygenase (LO) [36,37], and indoleamine-2,3-dioxygenase-1 (IDO1) [38].