Recently, the targeting of B7-family regulatory molecules was demonstrated to be a promising approach for the treatment of immune-related diseases, such as autoimmunity and cancer.1,2 This is illustrated by the ability of blocking monoclonal antibodies against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed death-ligand 1 (PD-L1) to enhance antitumour immunity in several solid tumours,3–6 including gynaecologic cancers.7–9. Here, CTLA4 is linked to cancer.