Effects of Belzutifan on 89Zr-DFO-girentuximab PET Uptake in Patients With Renal Cell Carcinoma (RCC)

This study is looking at how a drug called belzutifan affects the way a special PET scan tracer (89Zr-DFO-girentuximab) shows up in clear cell kidney cancer tumors. It helps researchers understand whether this tracer can be used to predict how well belzutifan is working. **You may be eligible if...** - You are over 18 years old - You have been diagnosed with advanced clear cell kidney cancer (clear cell renal cell carcinoma) - Your cancer has gotten worse on or after prior immunotherapy treatment - You have measurable disease on imaging - You have received at least two previous treatments **You may NOT be eligible if...** - Your cancer is not the clear cell subtype - You have not had prior immunotherapy - You have severe organ problems or uncontrolled other illnesses - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.