The NBA deal includes it, the MLB is attempting it, and the NFL has been advised to do it, but what is it? Playing in “the bubble” is basically not allowing players/families that are in the audience to leave the venue that the games are being played at. For example, NBA players would be required to stay at Disney World for the 3 months that are left in the season.
Does it work? Well, in theory this should be a great solution. But life is not theory and there will always be complications. Anyone involved could contract the virus.