Inclusion Criteria:
1. Provide signed written informed consent and voluntarily agree to participate in this study.
2. Age ≥ 18 years and ≤ 75 years.
3. Histologically confirmed colorectal adenocarcinoma.
4. Liver metastasis confirmed by imaging or pathology.
5. Have not received any prior anti-cancer therapy.
6. At least one measurable lesion according to RECIST v1.1.
7. pMMR/MSS status confirmed by a local testing center, or unknown status.
8. Be able to swallow tablets.
9. ECOG PS 0-1
10. Have no contraindications for surgery.
11. Have adequate major organ function.
Exclusion Criteria:
1. Have a history of allergy to monoclonal antibodies, any component of retlirafusp alfa, bevacizumab, capecitabine, oxaliplatin, or other platinum-based agents.
2. Have previously received or are currently receiving any of the following treatments:
1. Any anti-tumor therapy including surgery, radiotherapy, chemotherapy, targeted therapy, or immunotherapy.
2. Use of immunosuppressive agents or systemic corticosteroids for immunosuppressive purposes within 2 weeks prior to the first dose of study drug (at a dose \> 10 mg/day prednisone or equivalent). Inhaled or topical corticosteroids, and adrenal replacement therapy at doses \> 10 mg/day prednisone or equivalent, are permitted in the absence of active autoimmune disease.
3. Receipt of live attenuated vaccine within 4 weeks prior to the first dose of study drug.
4. Major surgery or severe trauma within 4 weeks prior to the first dose of study drug.
3. Have any active autoimmune disease or history of autoimmune disease, including but not limited to interstitial pneumonitis, enteritis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism, or hypothyroidism (patients on hormone replacement therapy may be considered for inclusion). Patients with psoriasis or childhood asthma/allergy that has completely resolved and requires no intervention in adulthood may be considered for inclusion, but those requiring medical intervention with bronchodilators are not eligible.
4. Have a history of immunodeficiency, including HIV-positive test, or other acquired or congenital immunodeficiency diseases, or a history of organ transplantation or allogeneic bone marrow transplantation.
5. Have poorly controlled cardiac symptoms or diseases, including but not limited to: (1) heart failure of New York Heart Association (NYHA) class ≥ II; (2) unstable angina; (3) myocardial infarction within 1 year; (4) clinically significant supraventricular or ventricular arrhythmias that have not been clinically intervened or remain poorly controlled after intervention.
6. Have experienced a severe infection (CTCAE grade \> 2) within 4 weeks prior to the first dose of study drug, such as severe pneumonia requiring hospitalization, bacteremia, or infectious complications; or have evidence of active pulmonary inflammation on baseline chest imaging, or have signs/symptoms of infection or require oral or intravenous antibiotic therapy within 14 days prior to the first dose of study drug (except for prophylactic antibiotic use).
7. Have active pulmonary tuberculosis infection by history or CT examination, or a history of active pulmonary tuberculosis infection within 1 year prior to enrollment, or a history of active pulmonary tuberculosis infection \> 1 year ago without adequate treatment.
8. Have hepatitis B (HBV DNA ≥ 2000 IU/mL or ≥ 10⁴ copies/mL), or hepatitis C (positive anti-HCV antibody and HCV RNA above the lower limit of detection of the assay).
9. Have been diagnosed with another malignancy within 5 years prior to the first dose of study drug, except for malignancies with a low risk of metastasis or death (5-year survival rate \> 90%), such as adequately treated basal cell carcinoma or squamous cell skin cancer, or cervical carcinoma in situ, which may be considered for inclusion.
10. Are pregnant or breastfeeding.
