Aldesleukin [interleukin-2 (IL-2)] induces durable complete responses in some kidney cancer and melanoma patients. Nivolumab is an investigational antibody drug targeting programmed death-1 (PD-1) as a treatment, demonstrating activity in multiple cancer types. An expanding complement of immunotherapeutics raises important issues regarding the best way to use them. There are issues beyond identifying an agent that provides the superior front-line response: when does one therapy potentiate another immune therapy? When is the capacity of immune response exhausted and an approach without immune mechanism the better therapy? In this case report, we present a patient with metastatic renal cell carcinoma with no tumor regression evident on a PD-1 blockade (given on an investigational trial), who then achieved near-complete response to bolus high-dose IL-2 therapy, maintaining a persistent response off therapy. This case emphasizes on the need to develop improved predictors of response to immune therapies, especially as they can be applied to optimize sequential immunotherapeutic modalities versus predict when to turn to alternative targeted agents in renal cell carcinoma, and is an example of efficacious IL-2 application as a second-line treatment.