Meta extends the functionality of Threads with deeper integration with the fediverse. Users can now indicate that they like posts and view replies from other platforms directly within threads. This means that if someone has published a post on Threads that is also shared on other platforms like Mastodon, they can now see replies from those platforms without having to switch between them.
However, you can’t answer these at the moment, which is a feature Meta plans to add in the future.
Source: The Verge
June 2024