Phase Ib: Dose exploration: To assess the safety, tolerability, and determine the recommended Phase 2 dose (RP2D) of BC3402 in combination with durvalumab in subjects with advanced hepatocellular carcinoma (HCC) Phase II: Dose Expansion: To assess the antitumor activity of BC3402 in combination with durvalumab in subjects with advanced HCC.

Inclusion Criteria:

1. Willing to participate in the study and sign an informed consent form;
2. Male or female aged ≥ 18 years and ≤ 75 years;
3. Patients with advanced hepatocellular carcinoma confirmed by histology or cytology, or cirrhosis which meets the clinical diagnostic criteria of hepatocellular carcinoma by the by American Association for the Study of Liver Disease (AASLD) (2018 edition);
4. ECOG performance status of 0 or 1;
5. HBV Patients with HBV infection must be treated with antiviral therapy to ensure adequate viral suppression prior to enrollment;
6. Adequate organ and marrow function;
7. Male or female subjects with childbearing potential must agree to use reliable contraceptive methods.

Exclusion Criteria:

1. Received local hepatic therapy within 4 weeks prior to initiation of the study drug;
2. History of hepatic encephalopathy within the past 12 months or a requirement for medications to prevent or control encephalopathy;
3. The subject has clinically significant ascites requiring therapeuticc peritonrocentesis or peritoneal drainage.
4. The subject has main portal vein thrombosis on baseline imaging;
5. Documented history of GI bleeding within the past 6 months or at a high risk of GI bleeding per the investigator's clinical judgement;
6. Current or prior use of systemic corticosteroids or other immunosuppressive agents within 2 weeks before initiation of study drug;
7. Prior treatment with any anti-TIM3 antibody;
8. Prior treatment with an anti-PD-1 or anti PD-L1 immune checkpoint inhibitor antibody (only applicable for dose expansion part).

Other protocol-defined Inclusion/Exclusion may apply.