Botensilimab + Balstilimab vs Best Supportive Care as Therapy in Chemo-refractory, Unresectable, Colorectal Adenocarcinoma

This trial is testing a combination of two immunotherapy drugs — botensilimab and balstilimab — versus standard supportive care for people with advanced colorectal cancer that has stopped responding to all available treatments. The cancer in this study is specifically the non-MSI-H (microsatellite stable) type, which typically does not respond to standard immunotherapy. **You may be eligible if...** - You are 18 or older - You have confirmed colorectal adenocarcinoma that is NOT microsatellite instability-high (MSI-H) - You have already tried and failed all standard treatment options - You are reasonably functional (ECOG score 0 or 1) - You have a life expectancy of at least 12 weeks - You can provide tumor tissue for research analysis - You can complete quality-of-life questionnaires in English or French **You may NOT be eligible if...** - You have a history of serious immune deficiency or organ transplant - You have taken immunosuppressive medications recently - You have an active autoimmune or inflammatory condition - You have active brain cancer spread - You have had recent bowel obstruction, severe diarrhea, or need repeated fluid drainage from the abdomen - You have previously received anti-PD-1/PD-L1 or anti-CTLA-4 immunotherapy - You have unresolved serious side effects from prior treatment Talk to your doctor to see if this trial is right for you.