Adding a shared SharePoint contact list to Outlook in new experiences. This exists in the classic experinece and is being removed on 26th November 2020. See this post https://answers.microsoft.com/en-us/msoffice/forum/all/adding-a-shared-sharepoint-contact-list-to-outlook/159428d9-7917-44bf-9598-b5e8eec3b42f