This study is a prospective, single-arm, multicenter exploratory clinical study aimed at evaluating the efficacy and safety of Fruquintinib combined With Serplulimab and chemotherapy as first-line treatment for RAS/BRAF-mutated unresectable advanced colorectal cancer. The study plans to enroll 80 patients with RAS/BRAF-mutated unresectable advanced metastatic colorectal cancer. After evaluation and confirmation of meeting enrollment criteria, patients will receive treatment with Fruquintinib combined With Serplulimab and chemotherapy . The primary endpoint of the study is PFS, and secondary endpoints include ORR, DCR, OS, and safety.