Over the past years, immune checkpoint inhibitors have been widely used for the treatment of a broad range of malignancies. Unfortunately, only a proportion of patients derives long-term benefit from these therapeutics. In fact, a majority of patients fails to respond to immune checkpoint inhibition, while others relapse after a certain time. In an attempt to increase the response rate of tumours to these drugs, investigators have looked into the potential of combining different immunotherapeutic agents. Since inhibitors of the immune checkpoints CTLA-4 and PD-(L)1 have different modes of action and given the fact that blocking one of both pathways results in an upregulation of the other, provide a theoretical rationale to combine these agents. This review provides an overview of clinical studies evaluating combinations of CTLA-4 and PD-(L)1 inhibitors in the treatment of melanoma, renal cell carcinoma and non-small-cell lung cancer.