**Study Summary** This clinical trial is testing a new drug called TT-702 in patients with advanced solid tumors. **Solid tumors** are abnormal masses of tissue that usually don't contain liquid areas. The trial aims to find the safest dose of TT-702 alone and when combined with other cancer-fighting drugs. TT-702 is a *small molecule prodrug*, meaning it turns into another active form in the body, called TT-478. This active form blocks a specific part of cells called the *A2B adenosine receptor*, helping the immune system fight cancer. The study has two phases: 1. **Phase I**: This phase tests increasing doses of TT-702 alone and with other drugs to find the best dose. It includes patients with specific types of tumors like colorectal cancer, prostate cancer, lung cancer, and more. 2. **Phase II**: This phase uses the best dose found in Phase I to treat more patients. **Key Points:** - The trial involves multiple visits and tests. - Participants must be at least 16 years old and meet health criteria. - Some patients might receive a combination of treatments. Patients considering this study should discuss potential risks and benefits with their doctor.