Metastatic sites and lesion numbers cooperated to predict efficacy of PD-1 inhibitor-based combination therapy for patients with metastatic colorectal cancer.

Patients with hypermutated mCRC benefited significantly from immunotherapy, whereas the non-hypermutated cohort with liver metastasis and numerous lesions showed less benefit. The lesion sites reflected varying levels of efficacy, among which PD-L1 potentially cooperated to guide the immunotherapy of CRLMs.