Palbociclib and Sasanlimab for the Treatment of Advanced Clear Cell Renal Cell Carcinoma (ccRCC) or Papillary Renal Cell Carcinoma (pRCC)

Background: Kidney cancer is the 12th leading cause of cancer-related death in the United States. Some kidney tumors do not respond well to current treatments. Better treatments are needed. Objective: To test a pair of drugs (sasanlimab and palbociclib) in people with kidney cancers. Eligibility: People aged 18 years and older with kidney cancer; specifically, clear cell renal cell carcinoma (ccRCC) or papillary renal cell carcinoma (pRCC). Design: Participants will be screened. They will have a physical exam with blood tests. They will have an imaging scan and a test of their heart function. They may have a biopsy; that is, a sample of tissue will be cut from the tumor. Participants will be treated in 28-day cycles for up to 2 years. Palbociclib is a pill taken by mouth. Participants will take this drug once a day for 21 days during each 28-day treatment cycle. They will write down the dates and times they take these pills in a diary. Sasanlimab is an injection under the skin. Participants will receive this injection on the first day of each treatment cycle. Imaging scans and blood tests will be repeated throughout the treatment. Tumor biopsies may be repeated up to 3 times; these biopsies are optional. Participants will have follow-up visits every month for 3 months after treatment ends. They will continue to have imaging scans every 3 months; these scans may be done close to home. The results can be sent to researchers. Participants will remain in the study up to 6 years.