This study is a prospective, single-arm, multicenter, phase Ib/II clinical trial that treats previously untreated patients with locally advanced or metastatic pancreatic cancer using mFOLFIRINOX in combination with anlotinib and sintilimab. The purpose of this trial is to evaluate the efficacy and safety of this treatment regimen and to preliminarily explore the correlation between biomarkers and treatment outcomes.

Inclusion Criteria:

1. Fully understand this study and voluntarily sign the informed consent form;
2. Age between 18 and 75 years inclusive, with no gender restrictions;
3. Patients with locally advanced or metastatic pancreatic cancer diagnosed by histology or cytology;
4. No prior anti-cancer treatment;
5. Patients must have at least one measurable lesion (according to RECIST 1.1 criteria);
6. ECOG PS score of 0-1;
7. Expected survival of at least 3 months;
8. No severe organic diseases of the heart, lungs, brain, liver, kidneys, or other organs;
9. Women of childbearing age must agree to use contraceptive measures during the treatment period and for 6 months after the end of treatment; negative serum or urine pregnancy test within 7 days before study enrollment, and must be non-lactating, men must agree to use contraceptive measures during the study period and for 6 months after the study ends.

Exclusion Criteria:

1. Have already received or are currently receiving additional anti-tumor treatment measures such as chemotherapy, radiotherapy, targeted therapy, immunotherapy, or traditional Chinese medicine treatment;
2. Known allergies to any of the drugs in the study;
3. Symptomatic brain metastases or metastases with symptom control time less than 2 months;
4. A large liver metastasis burden, occupying more than 70% of the liver volume;
5. Patients with obstructive jaundice whose bilirubin cannot be reduced to the expected level after adequate decompression;
6. Presence of any active autoimmune diseases or patients with autoimmune diseases expected to relapse (such as interstitial pneumonia, colitis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism, hypothyroidism, including but not limited to these diseases and syndromes);
7. History of immunodeficiency; patients currently using immunosuppressants, systemic corticosteroid therapy, or any other form of immunosuppressive treatment;
8. Known genetic or acquired bleeding tendencies (such as coagulation disorders) or thrombosis, such as hemophiliacs; currently using or have recently (within 10 days before the start of the study treatment) used full-dose oral or injectable anticoagulants or thrombolytic drugs for therapeutic purposes (preventive use of low-dose aspirin, low molecular weight heparin is allowed);
9. Serious infections (CTC AE greater than grade 2) occurred within 4 weeks before the first use of the study drug, such as severe pneumonia requiring hospitalization, bacteremia, infectious complications, etc.; baseline chest imaging suggests active pulmonary inflammation, presence of symptoms and signs of infection within 2 weeks before the first use of the study drug, or requiring oral or intravenous antibiotic treatment (excluding the use of antibiotics for prevention);
10. History of other malignant tumors within the past 5 years or concurrently, except for cured basal cell carcinoma of the skin, cervical carcinoma in situ, and papillary thyroid carcinoma;
11. Patients with mental illness; history of abuse of psychotropic drugs, alcoholism, and drug addiction;
12. Pregnant or lactating women;
13. Deemed by the investigator as unsuitable to participate in this trial for other reasons.