Gemcitabine and Albumin-Bound Paclitaxel Combined With Liposomal Irenotecan (II) With or Without SHR-1701 as Neoadjuvant Therapy for Resectable or Borderline Resectable Pancreatic Cancer

Inclusion Criteria: 1. Age ≥18 years, male or female; 2. Resectable or borderline resectable pancreatic cancer 3. No prior anti-tumor therapy (including radiotherapy, ablation, chemotherapy, targeted therapy, immunotherapy, etc.) or investigational drug treatment 4. At least one measurable lesion as a target lesion according to RECIST v1.1 criteria 5. ECOG performance status: 0-1 6. Expected survival time ≥3 months 7. Adequate major organ function Exclusion Criteria: 1. Patients with pancreatic tumors originating from non-pancreatic ductal epithelium, including pancreatic neuroendocrine carcinoma, pancreatic acinar cell carcinoma, pancreatoblastoma, and solid-pseudopapillary neoplasm 2. Known central nervous system (CNS) metastases 3. Severe gastrointestinal dysfunction (e.g., GI bleeding, obstruction, Grade \>2 inflammation, or Grade \> 1 diarrhea); 4. Symptomatic ascites requiring paracentesis or drainage, or patients who have received ascites drainage within the past 3 months (except for those with asymptomatic, controllable minimal ascites detected solely on imaging); 5. Current interstitial lung disease (ILD) or pneumonitis; 6. Known peripheral neuropathy (CTCAE Grade ≥3); 7. Coagulation dysfunction, bleeding tendency, or current thrombolytic or full-dose anticoagulant therapy. 8. Uncontrolled clinical cardiovascular symptoms or diseases； 9. Malignancy other than pancreatic cancer within 5 years prior to randomization, with the exception of adequately treated cervical carcinoma in situ, basal cell carcinoma, or squamous cell carcinoma of the skin； 10. Known hypersensitivity to liposomal irinotecan, other liposomal formulations, gemcitabine, nab-paclitaxel, retlirafusp alfa injection, or any component of these products； 11. Known Acquired Immunodeficiency Syndrome (AIDS), positive HIV antibody test, or active syphilis infection； 12. History of neurological or psychiatric disorders, including epilepsy or dementia