Phase II single-arm study of nivolumab and ipilimumab (Nivo/Ipi) in previously treated classical Kaposi sarcoma (cKS)

•This phase II study evaluated safety and efficacy of nivolumab and low-dose ipilimumab in previously treated cKS.•Resulted in a durable response: RECIST response in 87% of patients and complete pathologic response in 6 of 13 assessable patients.•With a median follow-up of 2 years the median PFS was not reached.•Molecular analyses suggested ‘immune-cold’ phenotype.•This study provides a new treatment option for cKS.