After two years of flirting with the idea, it looks like Mortal Kombat 1 will finally make Mileena and Tanya a couple. This comes from a Tanya character bio circulating online after her reveal at Comic-Con, which hints that the princess and her guard are in a secret, forbidden relationship.
The character bio mentions that Tanya has a "bond with Princess Mileena" - one which contradicts her vow of chastity. It also mentions that Tanya is "following her heart" despite these risks, strongly suggesting that this romance will play a role in the main story.
"As an Umgadi, Tanya is sworn to piety and chastity," reads the bio, mentioning her role in the elite guard that protects the royal family. "That is why her bond with Princess Mileena, were it known, would cause a scandal. By following her heart, Tanya risks not only her position but also her life."
This is backed up by what we saw in the trailer. When Mileena begins exhibiting symptoms of the Tarkatan disease, Tanya is quick to her side to comfort the princess. The way Mileena responds is also surprisingly tender for the fan-favourite killer, so it definitely seems like something is going on there. And much like their flirting in Mortal Kombat X, Rain is just sat there, third-wheeling the whole time.
Right now, we can't verify that the character bio that's circulating online is actually official, but the whole thing sure reads like it is. The same sources that shared the Tanya bio also shared Li Mei's, which has since been officially confirmed on the Mortal Kombat Twitter account. Given that the Comic-Con event isn't livestreamed, it's very possible that it flashed up on the screen there, and it will be shared with us later today, alongside Baraka's info.
Now that we know that both Tanya and Mileena are on the base roster, it makes a lot of sense that this will be the game where they finally get together. After some flirty banter in MKX, Mileena's ending in Mortal Kombat 11 saw her resurrect and marry Tanya. They even had a cute demon daughter together. Awww.
However, considering Tanya's vows, we probably shouldn't expect anything so domestic in the main story. Maybe in their arcade endings though, because they're allowed to stray from canon as much as they like then. Please, NetherRealm, just let these girlies be happy, yeah?