Human:→ CD69+CD103+ cells with a TRM phenotype are increased in the lamina propria of patients with ulcerative colitis (UC) and Crohn’s disease (CD)→ High levels of CD4+ TRM cells in IBD patients are associated with early relapse.Mouse:→ TRM cells expressing Hobit and Blimp-1 are key drivers of experimental colitis due to an adaptive-innate crosstalk mechanism. This evidence concerns the gene PRDM1 and ulcerative colitis.