MRC1 and mismatch repair cancer syndrome 1: PD-L1 positivity significantly correlated with TILs > 5% and MMR deficiency, and PD-L1-positive cases (overall and IC) showed significantly longer overall survival (OS) with both antibodies.The parameters “high grade,” “right-sidedness,” and “TILS > 5% regardless of MMR status” evolved as potential parameters for additional immunological treatment decisions.