The one who discovered this is Ron_Scottznbgr over on Reddit, he has uncovered a whole new secret menu and shared it with all of us to enjoy so we can enjoy it as well!.
Ron_Scottznbgr also gave us a video on how to open it.
Here is how to do it.
1. Open the data vault.
2. Go to top left area of the screen. You will be highlighting the weird “S” logo, and your cursor will disappear.
(Hitting “X” – PS4, or “A”- XB1 here will take you to the Dead Ops mode, although this is not at all necessary to get to the menu)
1. Hold all of the Shoulder Buttons, then press Square, then Triangle for PS4, or X,Y for XB1.
If that button combination fails to work, Hold RT and hit X then Y. Or hit X then Y then press RT.
GO TO PAGE 2 FOR THE VIDEO