IDO inhibitor 1 is primarily used in research to study the role of indoleamine 2,3-dioxygenase (IDO) in immune regulation and cancer therapy. It is employed to block IDO activity, which is often upregulated in tumors to suppress the immune system and promote tumor survival. By inhibiting IDO, this compound helps enhance the immune response against cancer cells, making it a valuable tool in immunotherapy studies. Additionally, it is used in preclinical models to explore its potential in treating autoimmune diseases and chronic infections where IDO plays a role in immune evasion. Its application extends to understanding the mechanisms of immune tolerance and developing strategies to modulate immune responses in various diseases.