A study on intratumoral microbiota and GC revealed that Methylobacterium tumefaciens was significantly associated with poor prognosis in gastric cancer patients and was negatively correlated with CD8+ tissue-resident memory T (TRM) cells and TGF-β in the tumor immune microenvironment (TIME).Experimental methods verified that Methylobacterium could reduce TGF-β expression and the number of CD8+ TRM cells in tumors. This evidence concerns the gene CD8A and gastric cancer.