Dose Escalation and Expansion Study of HM16390 Alone or With Pembrolizumab in Advanced or Metastatic Solid Tumors

Key Inclusion Criteria: * Have a histologically and/or cytologically confirmed advanced or metastatic solid tumor and have failed or are intolerant to standard therapy with clinical benefit. * Patients in the Dose-Escalation Part must have evaluable or measurable disease at baseline and the patients for Dose-Ranging and Dose-Expansion Part must have at least one measurable lesion at baseline by computed tomography (CT) or magnetic resonance imaging (MRI) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 assessed within 7 days before allocation or randomization. * Age of 18 years or older (or country's legal age of majority if the legal age was \>18 years) * Adequate renal function. * Adequate hematologic function. * Adequate liver function. Key Exclusion Criteria: * Received prior treatment with agent targeting the IL-2, IL-7, or IL-15 receptors, or related to mode of action of HM16390. * Known active CNS metastases and/or carcinomatous meningitis. * History of severe toxicities associated with a prior immunotherapy. * Any prior treatment-related (i.e. chemotherapy, immunotherapy, radiotherapy) clinically significant toxicities that have not resolved to Grade ≤ 1 per NCI-CTCAE version 5.0 or prior treatment-related toxicities that are clinically unstable and clinically significant at time of enrollment. * 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. * History of chronic liver disease or evidence of hepatic cirrhosis.