A preclinical study of PEGylated kynureninase, an enzyme that degrades kynurenine into an immunologically inert byproduct, thereby decreasing the pool of immunosuppressive AhR ligands, was associated with decreased tumor growth and increased CD8+ T cell infiltration in breast, melanoma, and colon cancer cell lines when combined with ICI therapy [18]. This evidence concerns the gene KYNU and melanoma.