Retinoic acid receptor-γ (RARγ) agonism is a key factor in CD8 T-cell-mediated immunity to infectious pathogens. The lack of studies on the effects of RARγ agonists on in vivo tumor growth of triple-negative (TNBC) or HER2+ breast cancers make it necessary to investigate whether RARγ could play a critical role in T-cell-mediated immunity in these breast cancers, using novel RARγ nuclear agonists.