This is currently in Preview – planned to release very soon.
In the following weeks, Teams will be rolling out support on Safari 11+ on macOS. While in preview, there are known issues with Safari’s ITP mode and it is advised that users disable Safari’s Intelligent Tracking Prevention.Tommiy commented
Unfortunately disabling ITP mode appears to only work with 10.14.3. With 10.14.4 teams is still inaccessible.Tommiy commented
3 months of testing? It must be finished soon surely?