This is an open-label, dose-escalation and dose-expansion study to determine the safety, tolerability, PK, pharmacodynamics, and preliminary efficacy of INCB123667 when administered as monotherapy and in combination with anticancer therapies in participants with selected advanced or metastatic solid tumors. This study will consist of 2 parts. In Part 1, INCB123667 will be administered as monotherapy and in Part 2, INCB123667 will be administered in combination with anticancer therapies of interest. Each part will comprise a dose escalation portion (Parts 1a and 2a, respectively) and a dose-expansion portion (Parts 1b and 2b, respectively).