This Phase 1/2 study evaluates the safety, tolerability, and preliminary anti-tumor activity of an allogeneic dual-target chimeric antigen receptor natural killer (CAR-NK) cell product in adults with advanced or metastatic colorectal cancer (CRC). Participants are assigned to one of three dual-target arms based on tumor antigen co-expression: (1) CEA+GUCY2C, (2) CEA+HER2, or (3) GUCY2C+HER2. Following dose escalation, the most suitable target pair (based on safety, feasibility, and early efficacy/biomarker signals) will be selected for dose expansion.