CTLA4 and breast cancer: In addition, NOTCH seems to play a key role in BC immunotherapy where NOTCH depletion resulted in an improved efficacy of nivolumab (anti‐PD‐1 antibody) and ipilimumab (cytotoxic T cell‐associated antigen‐4 (CTLA‐4) antibody) (Qiu et al. 2018)).