Natural killer (NK) cells have emerged as a major target for cancer immunotherapies, particularly as cellular therapy modalities because they have relatively less toxicity than T lymphocytes. However, NK cell-based therapy suffers from many challenges, including problems with its activation, resistance to genetic engineering, and large-scale expansion needed for therapeutic purposes. Recently, nanobiomaterials have emerged as a promising solution to control the challenges associated with NK cells. This focused review summarises the recent advances in the field and highlights current and future perspectives of using nanobiomaterials to maximise anticancer responses of NK cells for safe and effective immunotherapy. Finally, we provide our opinion on the role of smart materials in activating NK cells as a potential cellular therapy of the future.