This study is testing a new treatment called WTX-124 for people with advanced solid tumors (hard lumps of cancer cells). WTX-124 is a special kind of medicine that works with your body's cells to fight cancer. It will be given alone or with another medicine called pembrolizumab (also known as Pembro). This is a Phase I study, which means it's the first time this treatment is being tested in humans to see if it's safe and to find the right dose. The study has two parts: the first part will find the best dose of WTX-124, and the second part will test how well it works with Pembro.

• The study involves multiple visits, and participants must be 18 or older.
• Participants need to have specific types of advanced cancer and meet health requirements.
• Risks include potential side effects from the treatment; discuss with your doctor.

Before joining, you must have a tumor that can be measured and agree to have biopsies (tests on tissue samples). If you have had another cancer recently or certain health issues, you might not qualify. Participation involves using effective birth control during the study and after. Always talk to your doctor about the risks and benefits before deciding to join a clinical trial.