There exists substantial evidence suggesting that patients diagnosed with MSI-H/dMMR colorectal cancer can derive benefits from immunotherapy in the management of advanced colorectal cancer. In cases of locally advanced colorectal cancer exhibiting microsatellite instability (dMMR/MSI-H), patients exhibit low responsiveness to neoadjuvant chemotherapy, resulting in minimal rates of complete tumor remission and downstaging. Nevertheless, initial exploratory studies, characterized by modest sample sizes, reveal a favorable therapeutic effect of neoadjuvant immunotherapy in this particular patient population. Envafolimab monoclonal antibody, the first PD-L1 antibody developed and manufactured in China, possesses noteworthy practical and societal value in the context of exploratory clinical research on neoadjuvant immunotherapy for locally advanced MSI-H/dMMR colorectal cancer patients. The objective of this study is to evaluate the safety and efficacy of envafolimab monoclonal antibody (PD-L1) as neoadjuvant therapy for locally advanced MSI-H/dMMR colorectal cancer through a prospective, multi-cohort phase II clinical trial. Additionally, this study aims to investigate the effectiveness and safety of envafolimab monoclonal antibody in combination with CAPEOX as a neoadjuvant treatment regimen for locally advanced pMMR colorectal cancer.