IBI310 in Combination with Sintilimab in Patients with DNA Mismatch Repair Deficient (dMMR)/microsatellite Instability High (MSI-H) Locally-advanced or Metastatic Colorectal Cancer

Inclusion Criteria: 1. Histologically confirmed colorectal adenocarcinoma 2. Imaging confirmed locally-advanced or metastatic colorectal cancer 3. Measurable disease by CT or MRI 4. MSI-H confirmed by central lab 5. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 Exclusion Criteria: 1. Prior treatment with an anti-Programmed Death Receptor (PD)-1, anti-PD-L1, anti-PD-L2, anti-Cytotoxic T-Cell Lymphoma-4 Antigen (CTLA-4) antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways 2. Subjects with active,known or suspected autoimmune disease 3. Subjects with a history of primary immune deficiency 4. Subjects with severe infectious diseases