After nearly 70 years frozen in ice (shown at the end of Captain America: The First Avenger), Steve is still adjusting to a world where most people he knew are gone when Fury brings him in.
After returning the Stones, Steve stays in the past and lives his life with Peggy Carter. He comes back an old man and passes his shield to Sam Wilson.
The man out of time finally goes back to his own time and gets the life he lost.