A website was discovered over the weekend for "Citizen Skywatch," along with associated Twitter and YouTube accounts. The site is pretty empty right now, with nothing more than a stylized logo that offers no hint of what the term is connected to. However, server addresses in the WHOIS site lookup point to some connection with Take-Two and Rockstar Games.
There's no way of knowing what game this might relate to, though the timing of the website's discovery in relation to the start of Gamescom this week suggests we'll be hearing more very soon. The Rockstar connection means it probably has nothing to do with BioShock: Infinite or XCOM, two games in which the term "Skywatch" would seem to be relevant. Maybe GTA V...?