 Micro- and nano-robots are being developed to target cancer cells and deliver drugs or other treatments. These robots can be propelled by chemical reactions, physical fields, or biological systems, and can be guided using magnets, light, or chemotaxis. Recently, these robots have been used for chemotherapy, immunotherapy, photothermal therapy, photodynamic therapy, chemodynamic therapy, and multimodal tumour therapy. The potential of these robots is immense, but there are still many challenges to overcome before they can be used in the clinic. This article was authored by Jelly Sun and Yang Long Hu.