This is an open, one-arm study to evaluate the safety and efficacy of mRNA personalized tumor vaccine (tumor vaccine) encoding neonatal antigen in combination with Sintilimab injection for adjuvant prevention of postoperative recurrence of hepatocellular carcinoma.

Inclusion Criteria:

• Are ≥18 years old (including boundary values), without limitation of sex at time of consent.
• The patient was confirmed as hepatocellular carcinoma by histopathology or cytology after surgery, and the lesion was completely resected by surgery R0 (no residual tumor under postoperative microscope and naked eye), and no residual lesion or extrahepatic metastasis was confirmed by postoperative imaging (CT/MRI).
• The patient is at high risk of postoperative recurrence, and the tumor must meet the following characteristics: Patients with hepatocellular carcinoma IIb/IIIa as defined by the 2019 Chinese Staging System.
• The Eastern Oncology Consortium Physical State Score (ECOG PS) is 0 or 1, and the Child-Pugh rating is A

Exclusion Criteria:

• Known allergy to any tumor vaccine, adjuvant, Stintilimab Injection formulation, fluorouracil inj, oxaliplatin injcalcies;
• Tumor mutation load (TMB) was less than 2.0/Mb or neonatal antigen load (TNB) was less than 0.5/Mb or the predicted number of neonatal antigens was less than 15;