Well, its an sad news to all J-Pop fans, an legendary J-Pop boy group band Arashi annouced that they will go on hiatus by 31 December, 2020.
Here is the link on AramaJapan:
http://aramajapan.com/news/arashi-to-go-on-hiatus-in-2020/95027/
They'll start this at 31 December, 2020. So i guess 2020 Tokyo Olympics could be the last one thing they'll peform there as they we're selected by the Japan choice for the artists to peform.
(sorry for my poor English)