This is an open-label, dose escalation, Phase I study to evaluate the safety, tolerability, pharmacokinetics and efficacy of IBI939 in subjects with advanced malignancies

Inclusion Criteria:

1. Able to understand and willing to sign the ICF.
2. Adults 18 years of age or older.
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
4. Life expectancy at least 12 weeks.
5. Adequate organ and bone marrow function.

Eligibility Criteria：

1. Previous exposure to any anti-TIGIT antibody.
2. Participate in another interventional clinical study, except for the observational (non-interventional) clinical study or the survival follow-up phase of the interventional study.
3. Any investigational drugs received within 4 weeks prior to the first study treatment.
4. Receive the last dose of anti-tumor therapy within 4 weeks before the first dose of study therapy.
5. Immunosuppressive drugs were used within 4 weeks prior to the first administration of the study drug.
6. Medication requiring long-term systemic hormones or any other immunosuppression therapy.
7. Major surgical procedures (craniotomy, thoracotomy, or laparotomy) or unhealed wounds, ulcers, or fractures were performed within 4 weeks prior to the first dose of study therapy.
8. Primary central nervous system (CNS) malignancy, or untreated/active CNS metastases, or leptomeningeal disease.
9. History of autoimmune disease , present active autoimmune disease or inflammatory diseases
10. Positive human immunodeficiency virus (HIV) test.
11. Active hepatitis B or C, or tuberculosis.
12. History of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation.
13. Known history of hypersensitivity to any components of the IBI939 or Sintilimab.
14. Pregnant or nursing females.