This study is testing a new treatment, **DF6002**, alone and with another drug called **Nivolumab**. It is for people with advanced solid tumors, which are cancerous growths that can't be easily removed. Researchers want to see if DF6002 is safe and how well it works. The study will test different ways of giving the drug: **subcutaneous (SC)**, which means under the skin, and **intravenous (IV)**, meaning through a vein. They will find the strongest dose that people can handle without too many side effects and the best dose that could work against the cancer. **Key Points:** - Participants will have advanced cancers that don't respond to standard treatments. - The study will involve different ways of receiving the drug and checking for safety and effectiveness. - Some medical conditions or prior treatments might prevent participation. This study is important to find new ways to fight cancers that don't have other treatment options. Participants will need to meet certain health requirements to join and should talk with their doctor to see if they are eligible.

Please note that there might be some risks involved, and the study has specific inclusion and exclusion criteria.