Evaluate efficacy and safety of IBI310 (CTLA-4 antibody) in combination with Sintilimab, for neoadjuvant treatment of MSI-H/dMMR resectable colon cancer

Inclusion Criteria:

1. Signed the Informed Consent Form (ICF) and complied with the visit and related procedures stipulated by the plan;
2. At least 18 years old.
3. Primary colon adenocarcinoma was histologically confirmed.
4. Radiographic assessment showed a resectable stage IIB-III based on AJCC Stage VIII (cT4 or cN+ only).
5. MSI-H or dMMR.
6. Radical excision can be performed before neoadjuvant therapy after diagnosis by the investigator.
7. Have at least one evaluable lesion according to the RECIST v1.1 evaluation criteria.
8. The Eastern Cooperative Oncology Group performance status (ECOG PS) is 0 to 1.

Exclusion Criteria:

1. Previously received any antitumor therapy for the disease under study, including surgery, radiotherapy, chemotherapy, targeted therapy, immunotherapy, etc.
2. Prior treatment with anti-PD-1, anti-PD-L1, anti-programmed death receptor ligand 2 (PD-L2) or anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) or any other drug acting on T-cell co-stimulation or immune checkpoint pathways (such as OX40, CD137, etc.) and adoptive cellular immunotherapy.
3. Concurrent participation in another clinical study, unless participating in an observational (non-interventional) clinical study or in the survival follow-up phase of an interventional study.
4. Received any investigational drug or device treatment within 4 weeks prior to initial administration of the investigational drug.