A Study of HFB200603 as a Single Agent and in Combination With Tislelizumab in Adult Patients With Advanced Solid Tumors

The purpose of this study is to test the safety and tolerability of HFB200603 as a single agent and in combination with tislelizumab in patients with advanced cancers. There are two parts in this study. During the escalation part, groups of participants will receive increasing doses of HFB200603 as a monotherapy or in combination with tislelizumab until a safe and tolerable dose of HFB200603 as a single agent or combination therapy is determined. During the expansion part, participants will take the doses of HFB200603 as a monotherapy (optional arm) or in combination with tislelizumab that were determined from the escalation part of the study and will be assigned to a group based on the type of cancer the participants have.