AHR and infection: In infections like human cytomegalovirus (HCMV), HIV, and ZIKV, pathogens manipulate TRP metabolism to produce kynurenine and other endogenous AHR ligands, establishing a metabolic-immune interface conducive to viral latency and immune suppression (Kgatle et al., 2021; Anderson et al., 2021; Balaton et al., 2015).