Pokémon's anime is incredibly long-running, spanning from 1998 all the way to 2023, where Ash Ketchum's journey is finally coming to an end. Over the decades, he's met countless people and Pokémon, and many questions have been brought up surrounding the mysteries of Pokémon's universe. Many of these get answered over time, but there are still plenty of mysteries that don't get resolved by the time Ash's story reaches its conclusion.
Source：https://www.cbr.com/unsolved-pokemon-mysteries-after-ash-retired/
