If you want to configure VS Code for Microsoft C++ and make sure that its compiler is working. Working solutions have been mentioned in this post.

This latest instalment concerns bringing up the toolchain for using the Kick Assembler with VS Code to target the C64, initially via the VICE emulator.

Read: IntelliSense not working in VS Code 3] Reinstall C/C++ Maybe when installing C/C++ you have made some mistakes due to which Intellisense is unable to pick up libraries.