The 2021 Summer Olympics will not allow fans from abroad to attend the games. The decision came from the organizing committee for the Olympics. They basically said that no foreigners will be allowed access into Japan for the Olympic and Paralympic games. They said that recent and the ongoing situation in Japan and throughout the world make it for a very challenging situation for them.
I can agree with this decision. I'm sure it was a tough one for them to make. They'll be missing out on big opportunities with have no fans from abroad at the games. But it makes sense from a safety point of view.