How to create a task pane using C++/COM in MS Office?

Question

I know Office add-ins can be created by

1. Office.js
2. VSTO
3. COM

I implemented an add-in before using VSTO, after searching for the information on how to do that on the Microsoft website, I get nothing. Is it lost how to create Office add-in using C++/COM technology? I know some software still use COM add-ins, such as Grammarly, TeamViewer, FoxitReader. But how to create a COM add-in? Some ideas? Thanks.