In case a GameFly listing and two German retailers listing the game wasn't enough, yet another retailer has listed Call of Duty: Modern Warfare Remastered for a standalone release.
While a standalone release for Call of Duty: Modern Warfare Remastered has yet to be confirmed, the latest retailer who listed it might carry a bit more sway than its predecessors. Amazon Japan (found by Wario64) listed the game for a June 20th release on the PlayStation 4 and a July 20th release on the Xbox One.
These dates are the same dates found in the GameFly listing from the beginning of May.
Amazon Japan has removed the page from their store, but the screencap lives on.