The purpose of this study is to test the effectiveness, safety, and tolerability of Nivolumab (also known as Opdivo or BMS-936558) and Ipilumumab (also known as MDX-010 or Yervoy). Nivolumab and ipilimumab are antibodies (a type of human protein) that are being tested to see if they will allow the body's immune system to work against tumour cells. The immune system is the body's defence against cancer, bacteria and viruses. The effectiveness of nivolumab and ipilimumab in cancer of the kidney will be assessed by measuring the size of patient tumours via CT scans.