RecruitingDrug trialRetifanlimab and Ruxolitinib In Solid MalignanciesThe goal of this clinical trial is to learn what dose of ruxolitinib can be given safely together with retifanlimab in patients with metastatic renal cell carcinoma and non-small cell lung carcinoma. The main question it aims to answer is: What is the maximum dose of ruxolitinib that can be used safely in patients with metastatic renal cell carcinoma and non-small cell lung carcinoma, and will it work? Participants will: Take drug ruxolitinib twice a day and keep a diary of when they take ruxolitinib at home; visit the clinic for infusions of retifanlimab every 4 weeks; visit the clinic for checkups and tests.