This is a phase I/II study to investigate the safety, tolerability, and preliminary efficacy of GLS-012 monotherapy and in combination with GLS-010 in subjects with advanced solid rumor after progression on standard treatment.

Inclusion Criteria:

1. Patients who are willing to sign the informed consent form;
2. Aged 18-75 years, male or female;
3. Histologically confirmed diagnosis of a solid tumor;
4. Patients with advanced solid tumors after progression on standard treatment;
5. Subjects must have at least 1 measurable target lesion according to RECIST version 1.1；
6. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1；
7. Life expectancy more than 12 weeks;
8. Adequate organ function and bone marrow function as indicated by the screening assessments in the screening period;
9. Women of childbearing potential must use highly effective contraception during the study period and at least 6 months after the last study drug administration, and must have a negative blood pregnancy test within 3 days before study enrollment.

Exclusion Criteria:

1. Patients with irAEs of grade ≥ 3 in the previous immunotherapy, and the AEs of the last anti-tumor treatment have not recovered to grade ≤ 1, except for hypothyroidism/hyperthyroidism and dermatitis that have recovered to grade ≤ 2, and AEs with no safety risks judged by the investigators, for example, alopecia.
2. Patients with primary or secondary immunodeficiency, or patients who are receiving long-term systemic steroid therapy or any other form of immunosuppressive therapy within 7 days before randomization.
3. Use of corticosteroids or other immunosuppressants for systemic treatment within 14 days before the first study drug administration;
4. Known central nervous system (CNS) metastases;
5. Patients with severe hypersensitivity to macromolecular protein preparations/monoclonal antibodies in the past.
6. Patients with other malignant tumors within 5 years before screening, except cured cervical carcinoma in situ and cured skin basal cell carcinoma.
7. Cardiac clinical symptoms or diseases that are not well controlled.
8. Known hereditary or acquired bleeding and thrombosis tendency.
9. Patients with congenital or acquired immunodeficiency disorders (such as HIV-infection), or a history of organ transplantation.
10. Patients complying with any of hepatitis B surface antigen (HBsAg) positive and HBV-DNA copies being more than 2500 copies/ml (or 500 IU/ml); or positive HCV-RNA;
11. Patients with poor compliance or other conditions that are not suitable to participate in the clinical trial, as considered by the investigator.