The biggest challenge of removing GIL is to do it without breaking existing code. There's work on that. Here's a technical talk about why is it difficult[1].

The biggest challenge of removing GIL is to do it without breaking existing code. There's work on that. Here's a technical talk about why is it difficult[1]. [1] https://www.youtube.com/watch?v=fgWUwQVoLHo https://www.youtube.com/watch?v=fgWUwQVoLHo