Traditionally viewed as inert ‘shells’, research over the last decade has revealed that retroviruses play complex functional roles in the early stages of the viral life cycle. This is particularly true for HIV, where the capsid represents the host-pathogen as the virus journeys from the cell periphery to the nucleus. Work by us and others have revealed the molecular details of these interactions which have led to breakthroughs in our understanding of how the virus defeats the nuclear pore complex, enabling it to infect non-dividing cells. Furthermore, these discoveries paved the way for the discovery of Lenacapavir, the most potent pre-exposure prophylactic developed to prevent HIV spread. In our most recent work, we show that the approaches we took to study HIV are also accelerating research into HTLV, a neglected retrovirus which causes lethal cancers and degenerative inflammatory conditions, with Aboriginal Australians the worst affected communities in the world.