AllGamesBeta posted what it claims to be leaked screenshots of Doom 4, which it also goes on to claim as being "doomed" (cancelled), citing rumors. Close to two dozen of these screenshots can be found at the source. They reveal what [could have been] the setting of Doom 4, probably of the horrors unleashed on Mars (in Doom 3 and Resurrection of Evil) finding their way to Earth.
Go check out the screenshot right here.