Mapbox is first and foremost a 2D mapping tool that can do some limited 3D. Cesium is first and foremost a 3D mapping tool that can do some limited 2D.
Also while the Cesium core remains Open Source more and more of the tools and extras needed to make something really useful are starting to require expensive licenses.
Also while the Cesium core remains Open Source more and more of the tools and extras needed to make something really useful are starting to require expensive licenses.