Advances in human pluripotent stem cell (hPSC) technologies now make it possible to derive virtually any cell type of the human body, as well as organ-specific organoids. This has opened the study of human cell types that were previously inaccessible for technical or ethical reasons. Neurons of both the central and peripheral nervous systems are a prime example: for the first time, we can study human neurons directly in the context of brain development and disease. In this talk, I will present our work using hPSC-derived brain organoids to investigate how the brain microenvironment shapes human neurodevelopment. Finally, I will introduce the new 3D models we are developing to study neuron–Schwann cell cross-talk.