We report a case...After 6 months of treatment, imaging suggested near-complete clinical remission, and at the 18-month follow-up, the patient had a good quality of life and imaging showed no tumor recurrence. This case suggests that a good response to a combined targeted immunotherapy regimen can be achieved in patients with MSS metastatic colorectal cancer, in addition, it also suggests that TMB-H is a predictive biomarker for clinical benefit from immunotherapy in MSS metastatic colorectal cancer.