Hello everyone, I had the same issue with VS Code intellisense not showing up (for Unity API). I'm using Linux Lite 4.6(Ubuntu 18.04 LTS), AMD Athlon II X2, Unity (2019.2.8f1). My first steps were: - Install .Net SDK (v3.0) following instructions from official site (https://dotnet.microsoft.com/download); - Install VS Code. (Install C# extension); - Set Visual Studio Code as external editor (in Unity); and... nothing had happen. Then I decided to use MonoDevelop IDE and use it for editing Unity scripts (https://www.monodevelop.com/download/#fndtn-download-lin-ubuntu). I set external editor as Mono (not showing up in select box. You have to provide path to executable)... and it worked perfectly! But using MonoDevelop strangely increased my CPU usage to high values and i decided just for experiment use VS Code again! And it worked! Suddenly Intellisense started to work! That was solution in my case. Hope that this solution will work for you.