Mortal Kombat X's next DLC character is out tomorrow (or as early as tonight on Xbox One), which is the returning Tanya for Kombat Pack purchasers. She'll be out on June 9th for everyone else. The trailer for her can be seen below and we'll see if story mode gets her actual movelist instead of an existing template in when you fight her a couple times.
For those that bought the Kombat Pack with all four DLC characters, the first classic skins pack also comes out tomorrow featuring Liu Kang, Sonya Blade & Kano. There will be a Kombat Kast on NetherRealm's Twitch channel this afternoon that showcase more of Tanya especially her variations.
The next DLC character after Tanya is indeed the Predator and he'll likely be out next month. I don't think he'll make it in time for Evo and he is probably gonna be banned anyway if he comes out before it because of their cutoff date on DLC characters and patches.