We previously explored the differentially expressed immune checkpoint genes in the pancreas of T2D patients and healthy controls and identified six immune checkpoint genes, including CD44, CD47, SIRPA, HAVCR2, TNFSF9, and VTCN1 [13], that might link islet inflammation and β-cell dysfunction in the pathological processes of T2D. This evidence concerns the gene TNFSF9 and type 2 diabetes mellitus.