As for where that leaves us: It looks like Sora is missing in the Shibuya of 2007's The World Ends With You. Seeing as Kairi appears to be alive as per the ending movie, perhaps Sora had to sacrifice himself to save her, which has pushed him into this new world.

Is Sora dead in KH3?

Anyway, in the ending, Sora embarks on one last journey to save Kairi, who was punted off in the harrowing events of the finale. (Xehanort, being the big bad he is, dangles her over a cliff and then kills her.) Despite Donald and Goofy's insistence to come along, Sora says he must go it alone. ... So yes, Sora dies.

Is Sora in The World Ends With You?

The area seen in Kingdom Hearts 3 and the Shibuya in NEO The World Ends with You are two completely different places". ... Kingdom Hearts 3 showed us that Sora has ended up in Shibuya and Riku has ended up in Shinjuku, both of which are represented in The World Ends With You.