Our data reveal that CD26high T cells have enhanced multi-functionality (IL-17A, IFNγ, IL-2, TNFα, and IL-22), stemness properties (elevated β-catenin and Lef1), memory (long-term persistence and Bcl2 expression), and a rich profile of chemokine receptors (including CCR2 and CCR5), thereby enabling them to traffic to, regress mesothelioma and inhibit the growth of pancreatic tumors. The gene discussed is CCR2; the disease is mesothelioma.