Samus Aran's arrival on the Nintendo Switch might be happening before Metroid Prime 4, as an insider is claiming that a remake of Super Metroid and an HD version of Metroid Prime Trilogy are being developed for the Nintendo Switch. The most recent entry in the Metroid series was Metroid: Samus Returns for the Nintendo 3DS back in 2017, which was a remake of Metroid II: Return of Samus for the Game Boy and was well-received by fans and critics alike.
The Metroid series is due to receive a new entry on the Nintendo Switch in the future, as Metroid Prime 4 was announced at E3 2017. The fans will be waiting a long time for the next Metroid game, as it was later revealed that Nintendo wasn't happy with the quality of Metroid Prime 4 under the eye of Bandai Namco, so development was scrapped. The production of Metroid Prime 4 was started over from scratch, with Retro Studios (the developers of the original Metroid Prime trilogy) back on board. Metroid Prime 4 is not expected to be released for at least a few more years, so the only way to play any Metroid games on the Nintendo Switch is by subscribing to Nintendo Switch Online and playing the older entries in the series on the NES or SNES apps.
It's possible that some of the older Metroid titles are being remade for the Nintendo Switch. According to Game Revolution, an industry insider is reporting that a remake of Super Metroid and an HD version of Metroid Prime Trilogy are being developed for the Nintendo Switch. The HD Metroid Prime Trilogy is expected to launch in fiscal year 2020/21, while the Super Metroid remake would be released in fiscal year 2021/22.
There have been numerous rumors regarding an HD version of Metroid Prime Trilogy over the past year. There was a rumor linked to Best Buy about Metroid Prime Trilogy on Switch back in April, but it proved to be untrue. The running theory has been that the HD version of Metroid Prime Trilogy has been ready for a while now, but the unexpected delay of Metroid Prime 4 also led to it also being delayed, as Nintendo wants to release the trilogy in the run-up to the new game.
The idea of there being a remake of Super Metroid is also questionable. Nintendo has been remaking some of its older classics recently, most notably The Legend of Zelda: Link's Awakening. Super Metroid is one of the greatest Nintendo games of all time and it's certainly deserving of a modern remake (as was the case with Metroid II: Return of Samus being reimagined as Metroid: Samus Returns), but the original is already available on the Nintendo Switch. It's possible that the reception to Metroid: Samus Returns prompted Nintendo to commission a remake of Super Metroid, with MercurySteam back on board as developers, but nothing has been confirmed as of the time of writing.
Source: Game Revolution