Researchers from Guilin Medical University (GLMU) reported the discovery and preclinical evaluation of novel indoleamine 2,3-dioxygenase 1 (IDO-1) inhibitors as potential anticancer agents. Synthesis and optimization of a series of chromone-oxime derivatives containing piperazine sulfonamide moieties led to the identification of compound [I] as the lead IDO-1 inhibitor.