During the most recent episode titled "Stormborn," three characters from wildly different families seemed to be open to the idea of coming together: Tyrion Lannister, Daenerys Targaryen, and Jon Snow. To quickly recap, Melisandre visited the Mother of Dragons to tell her about the prophecy of Azor Ahai, a valiant warrior who was said to have been reborn as in the form of a man or a woman to battle evil. The Red Woman says that while she used to think Stannis was the Prince That Was Promised, now she has reason to believe it could be either Jon Snow or Daenerys.
The thought of being The One obviously piqued Dany's interest and she asked Tyrion to reach out to Jon so they could meet in person. Probably afraid he'd get obliterated by dragons if he didn't, Tyrion penned a letter to Jon requesting his presence. But he wrote something major that you might have missed (I know I certainly did).
On the surface, it might seem like a silly Tyrion-esque thing to write, but PopSugar notes that it's actually a callback to the first time Tyrion and Jon met in the series premiere episode, "Winter is Coming." If you recall, Tyrion said the following to Jon after he called him out for being a bastard son:
"Let me give you some advice, bastard. Never forget what you are — the rest of the world will not. Wear it like armor, and it can never be used to hurt you...All dwarves are bastards in their father's eyes."
Could this be the beginning of the most badass alliance the show has seen yet?