To Evaluate the Safety, Tolerability, and Preliminary Efficacy of XH001 Injection as Adjuvant Therapy in Patients With High-risk Recurrent Solid Tumors

Inclusion Criteria: * Provision of signed and dated informed consent form; * Aged between 18 and 70 years old, male or female; * Patients with high-risk recurrent solid tumors confirmed by pathology after radical surgery mainly include pancreatic ductal adenocarcinoma, biliary tract malignancies, hepatocellular carcinoma, gastric adenocarcinoma, etc. * Expected survival duration ≥12 months; * ECOG score of 0-1; * White blood cell count≥ 3.0×10\^9/L; Neutrophil count ≥ 1.0×10\^9/L; Platelet count ≥75×10\^9/L; Hemoglobin (Hb)≥ 90g/L; Creatinine clearance rate≥50mL/min \[calculated using the Cockcroft-Gault formula\]; Alanine aminotransferase ≤ 3×ULN (patients with hepatocellular carcinoma or biliary tract malignancy \<5×ULN); Aspartate aminotransferase ≤ 3×ULN ((patients with hepatocellular carcinoma or biliary tract malignancy \<5×ULN); Total bilirubin ≤ 3×ULN; Serum albumin \> 28g/L; Coagulation: Prothrombin time prolongation ≤ 4s; Exclusion Criteria: * There is evidence of tumor residue, recurrence or metastasis during screening; * Has a history of hepatic encephalopathy or liver transplantation; * Has clinical uncontrolled (requiring repeated drainage) pericardial effusion, pleural effusion and moderate or severe ascites; * Requires long-term systemic administration of antiallergic drugs, or has severe hypersensitivity reactions (\>=Grade 3) to XH001 injection and/or any of its excipients; * New cerebrovascular accidents within 6 months before screening (including ischemic stroke, hemorrhagic stroke and transient ischemic attack)； * Individuals who have experienced acute myocardial infarction, or have uncontrolled angina pectoris, uncontrolled arrhythmia, severe heart failure (NYHA heart failure classification standard\>= Grade III) and other cardiovascular diseases within 6 months before screening; * Patients with pancreatic ductal adenocarcinoma (PDAC) have the following conditions: 1) Borderline resectable pancreatic ductal adenocarcinoma; 2) Tumor tissue containing neuroendocrine tumor components (i.e., mixed type); 3) Pancreatic tumor types other than PDAC; 4) Persistent severe diarrhea after surgery; * Patients with biliary tract malignancy have the following conditions: 1) Pancreatic or ampullary cancer; 2) Unresolved biliary obstruction; 3) Insufficient surgical biliary drainage, and there are signs of infection; * .Subjects with hepatocellular carcinoma exhibit the following conditions: 1) The tumor contains components such as fibrolamellar hepatocellular carcinoma, sarcomatoid hepatocellular carcinoma, and biliary tract malignancy; 2) Received more than one cycle of adjuvant TACE after surgery or ablation; * Patients with gastric adenocarcinoma have the following conditions: severe postoperative complications (severe postoperative infection, anastomotic leakage and gastrointestinal bleeding); * Have active or poorly controlled severe infections; * .Patients with other malignancies within 5 years before enrollment, except for those with a history of appropriately treated and cured cervical carcinoma in situ, breast carcinoma in situ, or skin basal cell carcinoma; * Any history of autoimmune diseases (regardless of whether they are currently active),； * Who have previously received similar therapeutic tumor vaccines;