The two antibodies, nivolumab and ipilimumab, do not only target different immune cell receptors, they also regulate distinct inhibitory pathways and have therefore non-overlapping mechanisms of action. Anti-CTLA-4 therapies seem to drive T-cells into tumours, resulting in an increased number of intratumour T-cells and a concomitant increase in IFN-y. This in turn can induce the expression of PD-L1 in the tumour microenvironment, with subsequent inhibition of antitumour T-cell responses, but may also increase the chance of benefit from anti-PD-1 and anti-PD-L1 therapies. A combination treatment with anti-CTLA-4 (e.g. ipili-mumab) plus anti PD-1 (e.g. nivolumab) or anti-PD-L1 antibodies should enable the creation of an immunogenic tumour microenvironment with subsequent clinical benefit for patients.