When Meta announced Threads, their new Twitter competitor, they claimed in the very first paragraph that it would interoperate with Mastodon and other social networks based on the open-source ActivityPub protocol: The official Mastodon site responded with their own blog post to address frequently asked questions
This post may miss the point. Supporting ActivityPub may be a good way to circumvent Antitrust interventions after Twitter inevitably perished under Musk. Threads will be the biggest ActivityPub instance, but it won’t be the only one, it’s a federated network after all.