A request to film scenes for Avengers: Doomsday, submitted to a UK local authority, references a location from a prior MCU film that's scheduled to reappear.
According to BBC News, Marvel has applied for permission to construct a film set in Windsor Great Park and has asked the Royal Borough of Windsor and Maidenhead for access to the area in August.
The set design plans identify it as a specific site featured in a recent MCU film, which now appears set to make a comeback in Avengers: Doomsday — though some fans speculate this could still be a misdirection, as Marvel works to maintain its famously secretive production schedule.
Warning! Potential spoilers for Avengers: Doomsday lie ahead!