The concept of "Portable AutoCAD 2020" typically refers to unofficial, modified versions of the software designed to run from a USB drive without a standard installation. While these versions may seem convenient for working on the go, it is important to note that they are not officially supported by Autodesk and can present security risks or stability issues.
How To Run AutoCAD on Low-End Devices Without a GPU? - Vagon Portable Autocad 2020