The study of exoplanets has moved from an era of detection to an era of atmospheric characterization, driven by the launch and commissioning of JWST as well as improvements in ground-based observational facilities. This era of characterization will involve both deep studies of individual high signal-to-noise exoplanet atmospheres as well as shallow and broad studies of exoplanet atmospheric demographics. In this talk, I will describe how we can leverage both of these characterization methods alongside 3D models to study exoplanet atmospheres. I will specifically describe the application of detailed 3D GCMs including the impact of clouds, thermochemistry, and interior evolution on the circulation and emergent properties of hot gas giant exoplanets. I will then present work modeling the climate dynamics of temperate rocky exoplanets in order to determine how planetary, atmospheric, and host star properties impact their potential for habitability. I will finish by describing the extent to which habitable conditions on rocky exoplanets may be discerned with future observations.