This special issue of evolutionary applications focused on the evolution of cancer has provided a wealth of different viewpoints and results from leaders in the field. Together, these papers emphasize the importance of a broad perspective in order to understand why we and other animals get cancer, how it evolves within an individual, and what we can do about it. We can no longer take reductionist approaches that consider only the cancer cells and their genes. Instead, we need to understand how millions of years of evolution have guided strategies that shape cancer risk, why cancer risk varies across different animals, how cancer risk can vary in a population and be influenced by ecology (and influence this ecology), and of course how cancers evolve within us and the evolutionarily informed strategies to counter their impact. My goal here will be to "bring it all home," providing a refresher of lessons learned with added kibitzing.
Keywords: cancer evolution; cancer risk and oncogenesis; somatic evolution; transmissible cancers.
© 2020 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.