Despite Mortal Kombat 1 releasing in a little over a month's time, there's still a lot we don't know about it besides the characters that will be included. Most of the game's marketing has been focused on character inclusions, the most recent trailer showcasing Reptile, Havik, and Ashrah. There's been very little information regarding actual content and multiplayer modes, but a new pre-order retail listing in Brazil has given us the name of a new single player mode called "Invasions".
Since the mode was revealed via the back cover of the physical game, we don't have a lot to go on, but we do get a very small screenshot as well as a short description. Translated from its original language, the description says that the "Invasions" mode will let players "Travel the Mortal Kombat realms fighting each season's invasions in an all-new single player experience". That's all the info we have to go on, but that hasn't stopped fans from speculating.
Given that the the description says "seasons" we can probably assume this mode will include seasonal content that NetherRealm will release sporadically over a number of years. Other fans are assuming that this mode will be a World of Light inspired mode, the single player campaign section from Super Smash Bros. Ultimate that had you fighting souped up characters from the game. Fans think this could be something similar for a unique single player experience, though there's no indication that's the case.
As for when we might learn more about this new mode, it was recently announced that a new Kombat Kast episode will take place later this week, will include new details about Mortal Kombat 1 and a fancy showcase of characters such as Smoke, Ashrah, and Geras. It's possible we could get some more info on single player modes since we've been given so little info so far, and this retail reveal of the physcial box suggests that this mystery "Invasions" mode is going to be shown off pretty soon.
In other leaked news, it was also recently claimed by a Mortal Kombat insider that Shujinko is "one of the last Kameos" to be revealed. Obviously, this hasn't been confirmed as of yet, though this insider did leak the inclusion of characters like Darrius, Sektor, and Cyrax before they were officially revealed, as well as the fact that Retile will have both his lizard and human form. That means it's probably quite likely that all you Shujinko fans out there will have to settle for a Kameo fighter for now.