This is a multicenter, open-label, parallel-group, randomised, phase IIb trial. This study is to evaluate and compare the efficacy and safety of Ametumumab (anti-EGFR monoclonal antibody) combined with anti-PD-1 monoclonal antibody in first-line treatment of RAS wild-type colorectal cancer patients, as well as to assess the immunogenicity and pharmacokinetic profile and recommend dosing regimen for phase III clinical trials.Conditions and keywords.