Moving from 2.9 to 3.x cef is no longer supported (https://github.com/esri/arcgis-pro-sdk/releases) and is replaced by WebView2 control
Anybody upgrade any code using cef from 2.9 to 3.x that can share he/she experience?
We have a sample addin implementation of WebView2, which you can find here.
Documentation for the WebViewBrowser Control can be found here:
https://pro.arcgis.com/en/pro-app/latest/sdk/api-reference/topic74183.html
Hope this helps! If you have any particular questions, feel free to post!