Vscode is permissively licensed, but some of the Microsoft created extensions are proprietary, e.g. the C/C++ extension and the Pylance extension. They state in their license that they can only be used with Visual Studio and Visual Studio Code and crash if you try to use them with VSCodium for example.

There are open source alternatives, the basedpyright extension is better than Pylance and I've heard the clangd extension is good.