GZMB and colorectal carcinoma: Furthermore, we describe a novel and unique role for Granzyme B (GZMB) as a highly prognostic gene in CMS1 and CMS2 CRC, with immune cells being a major source of GZMB in CMS1, while GZMB expression in CMS2 CRC is rather a tumor-intrinsic property, and hence an alternative GZMB source that is worth exploring as a biomarker and to uncover novel biology in CRC.