A recent study in our group has shown that the expression of BTLA, TIGIT, KLRG-1, and 2B4 is not enriched on TILs compared with their counterparts in peripheral blood of cancer patients.78 Most importantly, we found that co-expression of specific IRs including Tim3 and PD-1 is highly prevalent on CD8+ TILs across different cancer types, such as in lung, kidney, and breast cancers. Here, KLRG1 is linked to cancer.