Based on these findings, efforts have been made to explore the synergistic potential of combining STING agonists with IDO inhibitors in cancer immunotherapy.[91] For instance, Syeda and colleagues developed a prodrug nanoplatform to enhance these combinatorial effects.[91b] They synthesized an esterase‐responsive prodrug by conjugating the STING agonist MSA‐2 to the IDO inhibitor NLG‐919 through an ester bond. Here, STING1 is linked to cancer.