First three-dimensional, first-principle simulations of core-collapse supernovae have become possible in the recent past. They demonstrate the basic viability of the neutrino-driven mechanism for powering the explosions of the majority of supernova progenitors. However, important questions still remain to be settled. These include basic technical aspects such as the influence of the numerical resolution or the method of the neutrino-transport treatment, as well as important physics aspects such as the initial stellar conditions and still missing physics, for example effects of muon formation and neutrino oscillations. The talk will review the current status of 3D supernova modeling and of our understanding of neutrino-driven explosions. It will also provide an outlook on current progress for answering the open questions mentioned.