PDCD1 and renal cell carcinoma: Another retrospective study of patients with renal cell carcinoma (RCC) bone metastases treated with ipilimumab/nivolumab found relatively low efficacy (21%) and median OS (25.6 months) (213), and, generally, patients with bone metastases responded poorly to the combination of PD-1 and CTLA-4 inhibitors (213, 214).