**Study Overview:** This research examines the use of a medicine called a PD-1 antibody along with bevacizumab and a type of chemotherapy called CAPOX as the first treatment for certain colon cancer patients. Specifically, it's for people whose cancer has a RAS mutation (a change in a specific gene), is microsatellite stable (MSS), and has spread to other parts of the body (metastatic colorectal cancer or mCRC). **Key Points:** - **Participation Requirements:** Participants must not have had previous treatments for their metastatic cancer and need to meet specific health criteria. - **Exclusions:** Individuals with certain other health conditions or who have had recent surgeries or treatments may not qualify. - **Study Details:** The study involves tests and check-ups to see how well the treatment works and to ensure it is safe. This study aims to find out if combining these treatments can effectively slow down or stop the growth of cancer in patients who haven't had prior anti-tumor treatment.