In the New Skool vs Old Skool trailer, I'm not certain but I figured someone on this sub would know if it's Old Raiden and Scorpion, with New Sub-Zero and Jax? :
Mortal Kombat 11 Ultimate | Media
News Archive - March, 2019 - Mortal Kombat Online
New 'Mortal Kombat 11' trailer pits old skool vs. new skool | Nerdly
Mortal Kombat 11: Old Skool vs. New Skool Trailer - Gamersyde