Inclusion Criteria:
1. Subjects voluntarily participate in this study, sign the informed consent form;
2. Age ≥18 years and ≤75 years;
3. Histologically or cytologically confirmed pancreatic ductal adenocarcinoma or adenocarcinoma.
4. Patients have not received prior systemic therapy for unresectable locally advanced or metastatic pancreatic cancer;
5. At least one measurable lesion according to RECIST 1.1 criteria;
6. ECOG Performance Status 0-1;
7. Estimated life expectancy ≥3 months;
8. Adequate major organ function (no medication for blood component, cell growth factor correction therapy is allowed within 14 days before randomization);
9. Women of child-bearing potential must agree to use a reliable, effective method of contraception from the time they provide informed consent until at least 120 days after the last dose of study drug is administered. HCG test must be negative. And must be non-lactating;
10. Male participants whose partner is a woman of child-bearing potential must agree to use a reliable, effective method of contraception from the time they sign an informed consent form until at least 120 days after the last dose of study drug is administered. Male subjects also have to agree not to donate sperm during the same period.
Exclusion Criteria:
1. Histologically or cytologically confirmed other pathological types, such as acinar cell carcinoma, pancreatic neuroendocrine neoplasms or pancreatoblastoma.
2. Patients with other malignant tumors within 5 years, except localized tumor that has been cured;
3. Known active or untreated brain metastases, meningeal metastases, spinal cord compression or leptomeningeal disease.
4. Patients with a history of life-threatening bleeding or a definite risk of bleeding within 6 months before randomization;
5. Has undergone major trauma or surgical treatment within 28 days before randomization or is expected to undergo major surgical treatment during the study period;
6. Poorly controlled hypertension (systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg) ；or have a history of hypertensive crisis or hypertensive encephalopathy;
7. Thrombotic or embolic events, such as cerebrovascular accident (including transient ischemic attack, cerebral hemorrhage, cerebral infarction), deep vein thrombosis, pulmonary embolism, etc., occurred within 6 months before randomization;
8. Patients who receive any prior treatments targeting the mechanism of tumor immunity, such as immune checkpoint blockades, immune checkpoint agonists, immune cell therapy, etc.
9. Active autoimmune disease requiring systemic treatment within 2 years before randomization, or autoimmune diseases that may relapse or require scheduled treatment judged by the investigator;
10. Subjects with active hepatitis B or C;
11. Patients with a known history of immunodeficiency or HIV positive;
12. The investigator assessed that it is not appropriate to participate in the study.
