In immune-mediated diseases like primary Sjögren’s syndrome (pSS) (56), primary biliary cholangitis (PBC) (57), inflammatory bowel disease (IBD) (58–61), rheumatoid arthritis (RA) (62), and type 1 diabetes (T1D) (63–65), the chemokine and cytokine milieu in inflamed tissues drives MAIT cell via various chemokine receptors such as CCR9, CXCR5, CXCR4, CXCR3, CCR6, and CCR10 (Figure 1). The gene discussed is CCR9; the disease is type 1 diabetes mellitus.