Abstract
Currently, the programmed death-1/programmed death ligand-1 and the cytotoxic T-lymphocyte-associated protein 4 are the two commonly targeted immune-checkpoint inhibition pathways. These drugs have significantly improved the prognosis of many cancer types. While immune-checkpoint inhibitors have revolutionised the treatment of many cancer types, the majority of patients still progress. Several treatment strategies have been pursued to improve current results. One approach is to combine two checkpoint inhibitors, currently with promising results in melanoma, renal cell carcinoma and a subset of non-small-cell lung cancer patients. The identification of new checkpoint targets could allow the field of immuno-oncology to evolve further. We will discuss one of the most promising immune-checkpoint targets currently under investigation, the T-cell immunoglobulin and mucin domain-3.