When two or more objects move relative to one another in vacuum, they experience a drag force, which, at zero temperature, usually goes under the name of quantum friction. This contactless non-conservative interaction is mediated by the fluctuations of the material-modified quantum electrodynamic vacuum and, hence, is purely quantum in nature. Numerous investigations have revealed the richness of the mechanisms at work, thereby stimulating novel theoretical and experimental approaches and identifying challenges and opportunities. In this Perspective, we provide an overview of the physics surrounding quantum friction and a perspective on recent developments.