TNFRSF9 and colorectal cancer: Previous studies have shown that ILA derived from Lactobacillus plantarum enhances IL‐12 production by modulating histone modifications and chromatin accessibility in dendritic cells, thereby activating CD8+ T cells to suppress CRC development.[30] In addition, the short‐chain fatty acid butyrate, produced by Roseburia intestinalis, can inhibit the development of colorectal cancer by activating cytotoxic CD8+ T cells.[31] We identified 3‐IAA as a key metabolite produced by P. distasonis through untargeted liquid chromatography‒tandem mass spectrometry (LC‒MS/MS).