Bellone et al. have recently reported on 131 endometrial cancers that POLE-mutated tumors were associated with improved PFS and displayed increased numbers of CD4+ and CD8+ TILs as compared to wild-type POLE tumors, and that PD-1 was overexpressed in TILs from POLE-mutated vs. wild-type-tumors [40]. Here, CD4 is linked to endometrial cancer.