Legendary has been slowly building its MonsterVerse quadrilogy to the monumental fight between Godzilla and King Kong in Godzilla vs. Kong. It's had a 2020 release window for as long as Legendary has been promoting the MonsterVerse as a thing, and confirmed that it was aiming for a March 13 release within the last couple of months. But reports started popping up stating that the film's release might be delayed in order to deliver the best experience for fans.
In a recent interview with License Global (as noted by @OMEGAGOMARU on Twitter), Executive Vice President Brand Development of Legendary Entertainment, Elie Dekel, talked up Legendary's excitement for their 2020 film slate and still has Godzilla vs. Kong marked for a Spring 2020 release as currently scheduled. So there doesn't seem to be a delay set in stone quite yet.
Noting that, "Beyond the films themselves, the MonsterVerse was mentioned to be bolstered not only be its line of comics/graphic novels(And collector's merch), but will also be bolstered by a in-the-works future release MonsterVerse mobile-game." This is in line with previous statements from Warner Bros. Studio bosses Toby Emmerich and Peter Roth, in which they were confident of Godzilla vs. Kong and still aimed for this window but were worried about fan response.
Given the poor critical and commercial reception for Godzilla: King of the Monsters, you can't blame Legendary for wanting to take more time for the final film in the quadrilogy, but it seems that Legendary has indeed become more confident in the film over its development.
Toho broke their silence on how the film is coming along too, with the most recent statement clarifying that Toho has yet to see any of the visuals of the film as of July, but their boss has been happy with what they've seen from the United States production so far.
Godzilla vs. Kong is currently slated for a release March 13, 2020, and it sounds like things are moving along perfectly. The final film on Legendary's MonsterVerse quadrilogy is officially described as such, "In a time when monsters walk the Earth, humanity’s fight for its future sets Godzilla and Kong on a collision course that will see the two most powerful forces of nature on the planet collide in a spectacular battle for the ages. As Monarch embarks on a perilous mission into uncharted terrain and unearths clues to the Titans’ origins, a human conspiracy threatens to wipe the creatures, both good and bad, from the face of the earth forever."