We don't know. No scientific evidence. Just guessing and discussions at this point which is perfectly fine.

I wouldn't be surprised if there are more universes besides our own. Perhaps interacting with one another. Our own universe is mind-boggling massive. Too big for the human mind to comprehend. So to find out infinite other universes exist would not surprise me.

I'm starting to wonder if humans will ever really know the true scale and nature of the universe.