Along with the expression of CD103 (integrin-αE) and CD69 surface markers, expression of immune checkpoint regulator genes such as PD-1, CTLA-4, TIM-3 and LAG-1 on TRM cells obtained from solid tumors, clonal expansion of PD-1+TIM-3+ TRM cells with high expression of proliferation and cytotoxicity markers, and enrichment of this specific cell type in lung cancer patients responding to PD-1 antibody therapy (9) suggest TRM cells are a promising target for checkpoint inhibitor antibodies to offer therapeutic benefit in a myriad of solid tumor types. The gene discussed is HAVCR2; the disease is lung carcinoma.