Inclusion Criteria:  Patients with radiologically or histologically confirmed postoperative Recurrent Pancreatic Cancer Patients with at least one measurable lesion (according to RECIST 1.1 criteria); Have not received gemcitabine-based regimen after surgery No systemic treatment after diagnosis of recurrence ECOG score 0-1 Expected survival ≥ 3 months; Liver function is essentially normal: absolute neutrophil count > 1500/mm ³; platelet count > 100,000/mm ³; creatinine less than 1.5 times the upper limit of normal or calculated creatinine clearance (CRCI) > 45 mL/min; total bilirubin ≤ 2.0 mg/dL; aspartate aminotransferase (AST) and alanine aminotransferase less than 2.5 times the upper limit of normal Appropriate to participate in this trial as assessed by the investigator before entering the study Male and female subjects of childbearing potential must agree to use an effective method of contraception throughout the study Signed Informed Consent Form  Exclusion Criteria:  Patients who only undergo abdominal laparotomy but do not undergo resection of pancreatic tumor tissue Received gemcitabine-based regimen after surgery Systemic treatment after diagnosis of recurrence Patients with previous allergic reactions to similar drugs Pregnant or lactating patients Presence of pericardial effusion, uncontrolled pleural effusion, or clinically significant ascites at screening (including detectable ascites or ascites requiring puncture and aspiration on physical examination at screening) History of interstitial lung disease, pneumonitis, or uncontrolled systemic disease, including diabetes, hypertension, pulmonary fibrosis, acute lung disease, etc Patients with severe cardiovascular diseases within 12 months before enrollment, such as symptomatic coronary heart disease, ≥ grade II congestive heart failure, uncontrolled arrhythmia, myocardial infarction, etc Presence of any active immunodeficiency or autoimmune disease and/or history of any immunodeficiency or autoimmune disease that may recur at screening (e.g., hypothyroidism or hyperthyroidism, interstitial pneumonia, enteritis, hepatitis, hypophysitis, vasculitis, myocarditis, etc) Use of steroids or other systemic immunosuppressive therapy 14 days prior to enrollment Patients with other previous malignancies who are not cured Immunodeficient patients, such as HIV-positive Uncontrollable psychosis