*during the 5 year "Snappening"*
While the Avengers were either considered to be too spread thin, presumed dead, and/or off world, other things things, unexplainable things started happening around the world. Most of it kept quiet out of fear, since people that were revealing themselves to have powers were soother being snatched up by local government officials, or were just straight up disappearing in the middle of the night, except for a select few who seemed asylum at a special school made for individuals with special gifts and talents.
A place where they could be around others gifted like them and and feel safe, while learning to control and use their gifts for the betterment of mankind.