The majority of evidence, particularly from human tumor data, points to an inhibitory role for TIM-3,24–28 and it is well documented that TIM-3 marks terminally exhausted cells in chronic viral infections and cancer.16 19 20 23 With this in mind and given the significant improvement by PD-1 blockade of Ptpn22KO CTL tumor control, we investigated the consequence of TIM-3 inhibition in Ptpn22KO cells. The gene discussed is HAVCR2; the disease is cancer.