Breaking boundaries: Current progress of anticancer NK cell-based drug development

•NK cells are safe in allogeneic applications and therefore are ideal off-the-shelf drugs.•NK cell-based therapeutics have shown satisfying safety profiles and promising efficiency in cancer treatment.•NK cells possess a reservoir of innate immune receptors targeting various types of cancer cells.•With proper engineering, NK cells can function as the universal anti-cancer drugs that are not restricted to HLA and cancer types.