A collaborative study led by the University of Pittsburgh uncovered that consumption of the artificial sweetener sucralose (marketed as Splenda) may impair patients’ responses to immune checkpoint inhibitor therapies in skin and lung cancers. Using mouse models and patient cohorts, researchers demonstrated that sucralose intake alters the gut microbiome, which mediates diminished immunotherapy efficacy and shorter progression-free survival. This discovery uniquely associates a widely used non-nutritive sweetener with compromised cancer immunotherapy outcomes, signifying an important consideration for dietary recommendations during treatment.