CD274 and breast cancer: Humanized IgG4 monoclonal antibody against PD‐1 expressed predominantly on T‐cells; inhibits the binding of PD‐L1 expressed on tumour and non‐tumour cells to PD‐1 and thereby blocking a major immunosuppressive pathway; approved to treat mismatch repair deficient (dMMR) advanced‐stage breast cancer that had emerged during or after therapy.