CPI-444 is primarily used in the field of oncology as an adenosine receptor antagonist. It is being studied for its potential to enhance the immune system's ability to fight cancer. By blocking adenosine receptors, CPI-444 helps to prevent adenosine from exerting its immunosuppressive effects, which can otherwise inhibit the activity of T cells and other immune cells. This makes it a promising candidate for combination therapies with immune checkpoint inhibitors, such as anti-PD-1 or anti-PD-L1 antibodies, to improve the efficacy of cancer immunotherapies. Research is ongoing to evaluate its effectiveness in treating various types of cancer, including melanoma, non-small cell lung cancer, and renal cell carcinoma.