Neoadjuvant/Adjuvant Sintilimab, Nab-paclitaxel, and Gemcitabine for Resectable/Borderline Resectable Pancreatic Cancer

Inclusion Criteria: * Signed informed content obtained prior to treatment * Age ≥ 18 years and ≤ 75 years * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Patients must have imaging evaluations to confirm that their pancreatic adenocarcinoma is resectable and borderline resectable. Patients must have histologically confirmed pancreatic adenocarcinoma, too. * Therapy-naïve for their pancreatic cancer. Patients should receive no anti-tumor treatment, including systemic chemotherapy, interventional chemotherapy, high-energy focused ultrasound, radiotherapy, immunotherapy, molecular targeted therapy, and anti-tumor Chinese medicine therapy. * No serious dysfunction in blood system, heart, lung function, or autoimmune system (refer to the respective diagnostic criteria) * White blood cell (WBC) ≥ 3 × 109/L; Absolute neutrophil count (ANC) ≥ 1.5 × 109/L; Platelets (PLT) ≥ 100 × 109/L; Hemoglobin (Hgb) ≥ 90 g/L * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\]/ alanine aminotransferase (ALT) (serum glutamic pyruvate transaminase \[SGPT\]) ≤ 2.5 × institutional upper limit of normal (ULN); Total bilirubin (TBIL) ≤ ULN; Creatinine (CRE) ≤ 1.5 × ULN * Prothrombin time (PT) and international normalized ratio (INR) ≤ 1.5 × ULN * Able to comply with research visit plans and other protocol requirements. Exclusion Criteria: * The diameter of the resectable tumor is ≤ 2 cm in imaging evaluation * Associated with other malignant tumors * Patients receiving anti-tumor treatment before neoadjuvant therapy, including systemic chemotherapy, interventional chemotherapy, high-energy focused ultrasound, radiotherapy, immunotherapy, molecular targeted therapy, and anti-tumor Chinese medicine therapy * Use of any other investigational agents * Patients with uncontrolled intercurrent illness including, but not limited to ongoing or active infection, internal hemorrhage, pancreatic leakage, bile leakage, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements * Pregnant or nursing women * History of allergic reactions attributed to compounds of similar chemical or biological composition to nab-paclitaxel, gemcitabine, or sintilimab * Patients who are using and need to use warfarin for a long period * Patients who are unwilling or unable to comply with study procedures * Patients who are expected to be out of the observation period for 14 days or more during the treatment