The development of Metroid Prime 4 was scrapped by Nintendo and restarted with Retro Studios, but it seems as if the game hasn't moved far along in development, as Retro Studios is now looking for an art director for the game.
Metroid Prime 4 was originally announced during Nintendo's E3 2017 Direct and it was later revealed that the game was being developed by Bandai Namco. Little was known about the game's development under Bandai Namco, as it was revealed in 2019 that the game wasn't matching up to Nintendo's high standards and was being scrapped. Metroid Prime 4 iss now being developed by Retro Studios, which was the company behind the first three games in the series.
It has only been a few months since the announcement of Metroid Prime 4 being scrapped and restarted, but there were some fans who held out hope for more information at E3 2019, which never came to pass. It seems that the development hasn't progressed very far, as Retro Studios has put out an advert on its Twitter page concerning an open position for the role of art director on Metroid Prime 4.
There are also other positions still open at Retro Studios, including a physics engineer, lead character artist, lead graphics engineer, and a lead cinematics artist.
It's not uncommon for video game developers to continue hiring staff throughout the run of a production, as companies like Naughty Dog and Square Enix have been hiring staff for The Last of Us Part II and the Final Fantasy VII Remake over the past few months. The nature of the positions at Retro Studios (most notably for the art director role) suggests that Metroid Prime 4 is still in the early stages of development and won't be released anytime soon.
The Nintendo Direct that was shown during E3 2019 revealed a killer lineup of games for the next twelve months, so it's not as if the Nintendo Switch is suffering from the lack of a Metroid title. The fans of the Metroid Prime series have waited a long time for the next true entry in the series and it seems they might be waiting a while longer.
Those interested in pursuing a career with Retro Studios and potentially working on Metroid Prime 4 can find all of the job applications here.