A prospective, single arm, interventional study. All patients will receive IV nivolumab 3mg/kg every two weeks and ipilimumab 1mg/kg every 6 weeks. Patients will be treated until disease progression or intolerable toxicity for a maximal period of two years, with an option to re-initiate therapy upon progression in patients with prior documented response to investigational therapy (unless treatment was held for progression of disease).