Some 40 years ago a metaphor was posed that cancer was such an insidious adversary that a declaration of war on the disease was justified. Although this statement was a useful inspiration for enlistment of resources, despite extraordinary progress in our understanding of disease pathogenesis, in most cases and for most forms of cancer this war has not been won. A second metaphor was about magic bullets-targeted therapies based on knowledge of mechanisms that were envisaged to strike with devastating consequences for the disease. The reality, however, is that targeted therapies are generally not curative or even enduringly effective, because of the adaptive and evasive resistance strategies developed by cancers under attack. In this Series paper, I suggest that, much like in modern warfare, the war on cancer needs to have a battlespace vision.