The Purpose of this study is to investigate the safety, tolerability, pharmacokinetics, and preliminary efficacy of hSTC810 monotherapy in participants with advanced solid tumors.

The study consists of a dose-escalation phase that will evaluate 6 dosing schedules of hSTC810. The first cohort will be single participant cohort. Subsequent escalation cohorts will use a standard 3+3 design, with the ability to backfill up to an additional 6 patients in each dose cohort.

Inclusion Criteria:

• Male or female aged at 18 ≥ years
• Capable and willing to give signed informed consent
• At least one measurable lesion as determined by RECIST Ver.1.1
• ECOG PS score ≤ 1
• Expected survival ≥ 12 weeks
• For female or male patients of reproductive potential: Agree to use contraception throughout the study and at least 6 months after the last dose.

Exclusion Criteria:

• Subject who has received anti-cancer treatment within 4 weeks prior to the first dose of study treatment.
• Subject who has received radiotherapy or major surgery within 4 weeks prior to screening.
• Any toxicity due to prior therapy that has not resolved to ≤ Grade 1 or returned to baseline by the time of starting study treatment.
• Subject with known severe (≥Grade 3) hypersensitivity to any checkpoint inhibitor.
• Clinically significant laboratory abnormalities.
• Subject with a history of another invasive malignancy within 3 years before the first dose of study drug.
• Subject with active central nervous system (CNS) metastases.
• Subject who requires high dose of steroids or other immunosuppressive medications.
• Subject with a history of autoimmune disease that has required systemic treatment in the past 2 years.
• Subject with active infection that requires systemic antimicrobial treatment.
• Subject with active HBV or HCV infection.
• Subject who has a known history of HIV infection.
• Subject with active tuberculosis.
• Subject with a documented history of a cerebral vascular event, unstable angina, myocardial infarction, or cardiac symptoms consistent with NYHA Class IV within 6 months prior to screening.
• Subject with a history of idiopathic pulmonary fibrosis, organizing pneumonia, drug induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening CT scan.
• Subject who has received a prior allogeneic stem cell or solid organ transplant.
• Subject with a positive coronavirus disease (COVID) test during screening.
• Subjects who have received a live attenuated vaccine within 30 days prior to screening.
• Subject with another underlying medical condition.