This study is testing a drug called INCB123667 on people with advanced solid tumors, which are serious growths like a lump in the body. The study has two parts: In the first part, participants will receive just INCB123667. In the second part, they will get INCB123667 along with other cancer treatments. The study aims to find out how safe and effective this drug is.

To join, you must be 18 or older, have a solid tumor that hasn't responded to other treatments, and be willing to provide a tumor sample. You should not have serious heart problems, untreated brain tumors, or any active infections. The study will be conducted in several phases where the dose of the drug will be gradually increased to find the best amount to use.

• The study may involve regular hospital visits for monitoring.
• Participation includes receiving experimental treatment that may help fight the tumor.
• There might be side effects, and the drug's effectiveness is not guaranteed.