IL2 and nonpapillary renal cell carcinoma: We present a patient with poor-risk metastatic ccRCC with sarcomatoid features and high PD-L1 expression whose disease progressed rapidly despite high-dose interleukin 2 (HD-IL2) and pazopanib, and who had a sustained partial response (PR) on nivolumab, as well as corresponding molecular imaging analysis of PD-L1 using immuno-PET in tumorgraft models.