RecruitingPhase 2Drug trialCetuximab, Irinotecan, Toripalimab in RAS/BRAF Wild-type Ultraselected Right-sided Colorectal Cancer StudyThe objective of this clinical trial is to evaluate the efficacy and safety of cetuximab combined with PD-1 inhibitor and irinotecan in negative ultraselection RAS/BRAF wild-type refractory right-sided metastatic colorectal cancer.