The two images released by a leaker seem fake but TheGamingRevolution confirms their authenticity because the images come from the Alpha for Black Ops Cold War.
The first image shows that there is some form of facility which players must enter. The snowy map itself looks like Crossroads which has already been confirmed for the full release of the game.
The clue could point towards the potential name of the new map, Die Maschine. The character is holding the Pelington 703 sniper and we can also see that under the mini-map it contains an instruction, perhaps in a similar way to how Black Ops 4 guided new players in Zombies.
The second image shows the exterior of a bunker that looks like the outside area of Nacht der Untoten, the very first Zombies map.
The images seem to show that we will be able to exit the bunker to face endless waves of the undead. According to rumors, when Black Ops Cold War releases on November 13th, two maps will be available: one in Vietnam and the other as a remake of Nacht der Untoten.
This is a rumor, so all of this information may be false or turn out to be true. Nothing has yet been formalized by Activision or Treyarch, so this information should be taken with a grain of salt. The beta will be open from October 8th for PS4 users and from October 15 for the Xbox One and PC - please note that October 15th will be an open beta for PS4 users.