PRF1 and lung carcinoma: Additionally, a retrospective analysis in a lung cancer cohort revealed greater overall survival in patients who had CD8+ TILs that expressed high levels of PD-1, LAG3, and TIM-3.46 These results verify the increase of CD8+ T cells that are co-expressing traditional exhaustion markers are not terminally exhausted, but rather still capable of secreting IFNγ in response to tumor antigen, as well as having increased cytotoxicity as evidenced by elevated Prf1 (Figure 7b).