Natural killer cells (NK cells) belong to the core of the immune system and play a great potential in tumor immunotherapy (Laskowski et al., 2022). Therefore, relevant research on NK cells are the focus in recent years and the future. NK cells belong to a cluster of differentiation (CD) 45+ innate lymphoid cells (ILCs), which are mainly CD3-CD16+CD56+ lymphocytes in the human body. NK cells can be divided into CD56bright (CD16low) with immunomodulatory effect and CD56dim (CD16+) with cytotoxic effect according to neural cell adhesion molecule (NCAM) (Hong et al., 2010). NK cells mainly belong to the CD16+CD56dim subtype in human blood. NK cells can kill certain target cells without antigen contact or antibody involvement but can play a recognition role by expressing multiple receptors, such as CD56 (Ziegler et al., 2017). After successful recognition, NK cells begin to function by either directly touching the target cells or activating other immune cells through an intermediary (Subedi et al., 2022, Tan et al., 2020). NK cells have different characteristics from other immune cells, so they have been frequently studied and applied in recent years. The specific objective of this review is to investigate NK cells at the forefront of cancer immunotherapy with immune potency, genetic engineering, nanotechnology. This review collects, elucidates and summarizes a large number of researches on the development and application of NK cells, especially on the immune function and disease targets of NK cells, which reveals the special value and good application prospects of NK cells.