This Phase II clinical study evaluates the safety and efficacy of a combination therapy for patients with pancreatic cancer that has spread to the liver. Because liver metastases are a major factor in the progression of pancreatic cancer, this research utilizes Hepatic Arterial Infusion Chemotherapy (HAIC) to deliver high-concentration treatment directly into the tumor's blood supply. The multi-step strategy involves first infusing Sodium Bicarbonate to neutralize the acidic tumor microenvironment , followed by the NASOX chemotherapy regimen (Oxaliplatin and Liposomal Irinotecan) and an intra-arterial PD-1 inhibitor to boost immune response. Patients also receive oral S-1 to maintain treatment effect. The primary goal is to determine if this integrated approach can improve Overall Survival for patients compared to historical standard treatments.