Gears of War twitter account have shared new characters coming to Gears 5 multiplayer.
Sid Redburn and Mikayla Dorn are characters from Gears Tactics. If you already have played Tactics before a certain date back in December you would would receive Gabe Diaz, however.
From the image below:

Those that was unfortunate that didn’t get Gabe could be in look. For current players that have already Gabe, perhaps a new skin? More details to follow.
Source: Gears Of War