Dose Escalation and Expansion Study of BH3120 Alone or With Pembrolizuamb in Advanced or Metastatic Solid Tumors

Key Inclusion Criteria: * Have a Histologically or cytologically confirmed non-CNS solid tumor that is metastatic or unresectable and for whom there is no available standard therapy. * PD-L1 positive expression (Tumor Proportion Score ≥1% or Combined Positive Score ≥1). * Have at least one lesion, not previously irradiated that can be accurately measured per RECIST version 1.1. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Age of 18 years or older (or country's legal age of majority if the legal age was \>18 years) * Adequate Hematologic and liver function. Key Exclusion Criteria: * Has received prior therapy with an anti-4-1BB(CD137) agent. * Known active CNS metastases and/or carcinomatous meningitis. * Known additional malignancy that is progressing or has required active treatment. * History of chronic liver disease or evidence of hepatic cirrhosis. * History of severe toxicities associated with prior immunotherapy, except for adequately controlled endocrine-related adverse events managed with hormone replacement therapy. * Has ongoing or suspected autoimmune disease. * Known active and clinically significant bacterial, fungal or viral infection including known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS)-related illness, immunocompromised patients.