**Study of PYX-201 in Advanced Solid Tumors** This study is testing a new drug, PYX-201, for people with advanced or recurrent solid tumors. A solid tumor is a lump of cancer cells. The study will find the best dose and see if the drug helps shrink the tumors. Participants need to be adults (18+), have a type of cancer that has spread or isn't responding to treatment, and be in fairly good health. They must also have a life expectancy of more than 3 months and at least one tumor that can be measured for changes. **Key Points:** - **Study Duration & Visits**: The study may require multiple visits, as it tests the drug's effects over time. - **Risks**: Participants should consider potential side effects and their current health conditions. - **Exclusions**: Certain health issues or past treatments might prevent participation, like recent infections or specific past cancer treatments. The study will not accept anyone with other serious health problems, like heart disease or active infections. If you join, the research team will closely monitor your health and the tumor's response to the drug. This study aims to offer new hope for those with challenging cancers.