CTLA4 and cancer: The clinical success of immune checkpoint blockade with anti-cytotoxic T-lymphocyte-associated antigen (CTLA)-4 and anti-programmed death (PD)-1/PD-ligand (L)1 agents in melanoma and other cancers has encouraged increasing focus on the development of other immunotherapies, particularly monoclonal antibodies with other immune targets, adoptive cell transfer and vaccines.