'I'm Here For the Kid'
We previously suspected that Julian Dennison of Hunt for the Wilderpeople plays Deadpool 2's take on Hope Summers, who in Marvel comics is the mutant messiah Cable travels into the past to protect. However, this trailer states outright at Josh Brolin's cybernetically enhanced mercenary is out to kill this kid, who still hasn't been named.
Presumably Cable's vendetta has nothing to do with the boy delivering a double dose of the one-finger salute, and everything to do with his mutant abilities (note the telltale power-suppression collar, as well as his glowing hands in the later scene, amid the debris and overturned police car).
Back to the Future
We had theorized that the first trailer didn't depict Wade Wilson infiltrating some kind of mutant detention center but instead hinted we would see the character in two time periods: the present, and in the dystopian future from which Cable originates. We're guessing it's a very near-future, and that Cable believes the mysterious kid played by Julian Dennison is somehow responsible for creating that grim-dark world.
From there it undoubtedly gets a little fuzzy and a lot more complicated -- it's time travel, after all! -- as we try to untangle how future-Wade might have hidden the kid, and why present-Wade gets involved. So, we'll just ... walk away.
'I Can't Do This Alone'
On the rare occasion when Dopinder just isn't enough, sometimes you have to form your own team of misfit mutants. Not Negasonic Teenage Warhead and Colossus from the X-Men -- your own team of mutants. In fairness, Marvel Comics' X-Force started as a re-branding of the New Mutants, effectively the X-Men junior team, so perhaps it's to be expected that Deadpool would start his recruitment drive and Xavier's School for Gifted Youngsters. (Yes, Domino, it is a little derivative.)
Although Negasonic Teenage and the pink-haired character whom we think is Surge accompany, or at least cross paths with, Deadpool in the field, it's unclear from the trailer whether they actually join his motley crew.
X Marx the Spot
The shot of Wade Wilson's tender embrace of Colossus actually debuted in the international trailer released in February. What may have escaped notice is the portrait on the stairway of what we can presume is Charles Xavier's mansion. That's German philosopher and revolutionary socialist Karl Marx, author of The Communist Manifesto and Das Kapital.
Either Professor X is more radical that any of us previously realized, or that's a nod to the Soviet-era upbringing of Piotr Rasputin, aka Colossus. Or, hey, both.