Combined Locoregional Treatment With Immunotherapy for Unresectable HCC.

Inclusion Criteria:

1. Age: 18 - 80 years old and life expectancy of at least 12 weeks.;
2. Clinically or histologically diagnosed as HCC and the diameter of target tumor lesion ≥ 5 cm;
3. Child-pugh classification A or B (score \< 7);
4. BCLC Staging as B or C;
5. ECOG 0-1;
6. Patients voluntarily entered the study and signed informed consent form (ICF).

Exclusion Criteria:

1. History of treatment with any local treatment (exception of liver transplantation), systemic .anti-cancer therapy, or immunotherapy;
2. The surgeon assessed that the tumor lesion was not unsuitable for microwave ablation;
3. Any contraindications for hepatic embolization procedures:

   1. Known hepatofugal blood flow;
   2. Total thrombosis of main portal vein.
4. The tumor thrombus of main portal vein, IVC or right atrium;
5. Tumor burden ≥ 70% of liver volume; and no measurable site of disease as defined by modified RECIST (mRECIST) criteria with spiral CT scan or MRI;
6. Subjects with chronic HBV infection have HBV DNA viral load \> 100 IU/mL at screening, and have not received antiviral therapy prior to initiation of study therapy; In addition, coinfection of HBV and HCV;
7. The alcoholic or pregnant women;
8. Patients with second primary cancer or history of other cancer within 3 years;
9. Diagnosis of active autoimmune disease, immunodeficiency, or patient is receiving chronic systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of Sintilimab-monotherapy treatment;
10. Blood count, liver function: Haemoglobin \< 9.0 g/dL, white cell count \< 1.0 x10\^9/L; Total bilirubin \> 3 mg/dL; Aspartate Aminotransferase (SGOT) or Alanine aminotransferase (SGPT) \> 5 x upper normal limit (ULN), Albumin \< 2.8g/dL; International normalized ratio (INR) \>2.3;
11. Renal function dysfunction: Serum Creatinine \>2 mg/dL or creatinine clearance (CrCl) \< 30 mL/min (if using the Cockcroft-Gault formula ); and severe heart, lung, brain or other organ disease;
12. Non-compliance with TACE or ablation procedure.