Nanoparticles for cancer applications are increasingly able to move, sense, and interact the body in a controlled fashion, an affordance that has led them to be called robots. The challenge is to discover how trillions of nanobots can work together to improve the detection and treatment of tumours. Towards this end, the field of swarm robotics offers tools and techniques for controlling large numbers of robots with limited capabilities. Our swarm strategies are designed in realistic simulators using bio-inspiration, machine learning, and crowdsourcing. Strategies are then translated to 1000-robot swarms or preliminary tissue-on-a-chip devices.