QL1706 Plus Bevacizumab for Unresectable or Metastatic MSI-H/dMMR CRC

Inclusion Criteria: * Voluntarily signs the informed consent form. * Aged between 18 and 80 years (inclusive) at the time of consent; no gender restriction. * Histologically confirmed unresectable locally advanced or metastatic colorectal cancer. * At least one measurable target lesion according to RECIST v1.1. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * No prior immunotherapy for unresectable locally advanced or metastatic colorectal cancer. * If previously treated with standard neoadjuvant or adjuvant therapy, the interval from the last dose to the first study treatment must be ≥ 6 months. * Willing and able to provide tumor tissue and blood samples for MSI, RAS, BRAF, and PD-L1 testing. * Estimated life expectancy of ≥ 12 months. * Appropriate laboratory values must be met at screening. * Female participants must be non-lactating, and have a negative pregnancy test result prior to enrollment. * Participants of childbearing potential must agree to use effective contraception from the time of informed consent until at least 180 days after the last dose of study treatment. Exclusion Criteria: * Known history of severe allergic reactions to iparomlimab and tuvonralimab or bevacizumab. * Active malignancy other than colorectal cancer within 5 years prior to first treatment. * Large tumor lesions, especially those previously irradiated, with signs of bleeding. * Imaging showing tumor invasion of major blood vessels (e.g., pulmonary artery or superior vena cava), including encasement or invasion of the vessel lumen. * Brain metastases (asymptomatic or treated symptomatic brain metastases stable for \>4 weeks allowed). * Active autoimmune disease requiring systemic treatment. * Active pulmonary diseases such as tuberculosis, radiation pneumonitis, drug-induced pneumonitis, or severe pulmonary dysfunction during screening. * Requirement for long-term or high-dose NSAIDs (aspirin \>325 mg) or anticoagulant therapy. * History of severe gastrointestinal events within 6 months prior to first treatment. * Severe intestinal obstruction symptoms or signs and unretrieved intestinal stents at screening. * Cardiovascular or cerebrovascular diseases including but not limited to: NYHA class \> II heart failure; unstable or severe angina; myocardial infarction or stroke within 6 months; atrial fibrillation or other arrhythmias requiring treatment; symptomatic superior vena cava syndrome; prolonged QT interval (male QT \> 450 ms; female QTc \> 470 ms); uncontrolled hypertension despite medication (SBP \>140 mmHg and/or DBP \>90 mmHg) or history of hypertensive crisis or encephalopathy. * Known bleeding disorders or coagulopathies. * Uncontrolled pleural, pericardial, or ascitic effusions requiring drainage. * Active infection or unexplained fever \>38.5°C at screening (cancer-related fever allowed). * Use of systemic broad-spectrum antibiotics within 30 days prior to first treatment. * Systemic corticosteroids (\>10 mg prednisone equivalent daily) or immunosuppressants within 14 days prior to first treatment, or immunostimulants within 4 weeks. * Major surgery, severe fractures, or therapeutic clinical trials within 4 weeks prior to first treatment; herbal treatment within 2 weeks. * Ongoing adverse events from prior antitumor therapy greater than grade 1. * HIV infection, other congenital or acquired immunodeficiencies, or history of organ or allogeneic bone marrow transplantation (except corneal transplantation). * Positive hepatitis B surface antigen (HBsAg) and/or hepatitis B core antibody (HBcAb) with HBV DNA \>10⁴ copies/mL (\~2000 IU/mL); or positive hepatitis C antibody with HCV RNA \>10³ copies/mL; co-infection with HBV and HCV excluded. * Vaccination with live or attenuated vaccines within 30 days prior to first treatment. * Prior treatment with immune checkpoint inhibitors (e.g., anti-PD-1, anti-PD-L1, anti-CTLA-4, anti-OX-40, anti-CD137). * Prior adjuvant targeted therapy against EGFR, VEGF, or VEGFR (e.g., bevacizumab, cetuximab, panitumumab, apatinib, regorafenib, anlotinib). * Psychiatric disorders, epilepsy, dementia, or substance abuse that may affect compliance. * Other conditions or lab abnormalities that may interfere with study participation or confound results as judged by investigators or sponsors.