Patients with advanced melanoma whose cancer does not respond to treatment with widely used immunotherapy drugs known as PD-1 inhibitors are often switched to treatment with a second type of immunotherapy drug—a CTLA-4 inhibitor such as ipilimumab. New results from show that these patients are more likely to benefit from ipilimumab when it is given in combination with the PD-1 inhibitor nivolumab than when given alone. Patients in the study who got an ipilimumab and nivolumab combination had longer progression-free survival (PFS) time than patients who were treated with ipilimumab alone (six-month PFS estimates of 34% vs 13%). The overall...