According to the rumors, of the new features that will be introduced to the sequel will come in the form of a playable Zelda. While the game is named after Zelda, the main character that players control in the game is Link. The rumors are saying that with the sequel, Zelda might be a playable character, albeit in limited scope as she will only be playable while in dungeons.
This suggests that there could be some kind of buddy mechanic that is not uncommon in many RPGs. This would also allow for the creation of more complex puzzles that players will have to solve using both characters, and it has also been suggested that some of them might even require Zelda to use her triforce abilities.
Needless to say that this should be taken with a grain of salt for now, but with Nintendo confirming that they will be at E3 2020, hopefully more details about this sequel will be revealed then. As it stands, there is still no word on when the game will be released, but we wouldn’t be surprised if it were to arrive at the earliest in 2021.