In-universe, Yoda reflects that he and other Jedi Masters felt a surge in the Force about three years before the current storyline, but it takes meeting Steve, Sam, and Scott for Yoda to tentatively identify the date of that surge as the day the Avengers first came together.
Chapter 19 sees Nick Fury begin to tell Tony, Clint and Hank- the current 'active' Avengers left on Earth- about another potential recruit who he has kept secret up until now on the request of Bruce Banner; with Fury describing this recruit as Bruce's family, she has been all but explicitly identified as Bruce's cousin Jennifer Walters, before she finally appears in Chapter 54.
In Chapter 24, Gamora reveals that two of her 'brothers' can use the Force, with one of them being a 'fanatic loyalist' while the other disappeared on a mission for Thanos years ago, and Peter Quill discovers evidence that one of Ego's other children (and hence one of his own half-siblings) is somewhere in the Star Wars galaxy; Chapter 71 identifies that sibling as Asajj Ventress.
Chapter 29 ends with Ultron making a deal with the Hutts to be granted a location in this galaxy to conduct his work in return for not distributing certain confidential materials he acquired about their activities; chapter 30 hints that he has downloaded plans to a droid factory being built by the Seperatists, and chapter 32 shows both sides observing hints that Ultron has infiltrated such a factory. He ultimately goes "public" with his presence in Chapter 47.
In Chapter 31, after meeting Krennic, Chirrut mentions a grave sense of millions of voices crying out in terror and being suddenly silenced if that man is allowed to continue his existing plans, foreshadowing his role in the creation of the Death Star.
In Chapter 48, when Rex mentions how Ultron spoke of the clones turning on the Jedi with a simple order, Natasha, Matt, Yoda and Peter all notice a subtle reaction from Palpatine at this all-but-explicit reference to Order 66.
While checking in with Chirrut during Chapter 61, Daredevil learns that both the Protectors and The Ravagers have taken up protecting the planet, making it clear that it's only a matter of time until the Guardians of the Galaxy and Avengers meet up. After the Guardians meet the Vision in Chapter 67, Gamora, Mantis and HK-47 meet the other united Avengers the following chapter (at a point when Wanda is the only hero still absent).
When Ahsoka has a vision of her future self on Mortis, the older Ahsoka reflects on how Peter and Barriss help to balance Ahsoka and themselves out by each offering different perspectives, but the older Ahsoka also warns her past self of a coming darkness.
During his duel with the Son, Anakin experiences visions of a dark figure that is clearly Darth Vader and a tall figure that is all but explicitly identified as Thanos, followed by a vision of everyone Anakin knows turning to dust.
During his time on Tython, Peter experiences a "glitch" that resembles what happened to the displaced Spiders in Spider-Man: Into the Spider-Verse, linking back to the Father referring to Peter as a "totem of the Web". A few chapters later, Peter meets a version of himself who was born in the Galaxy Far, Far Away and trained as a Jedi before the two are pulled into another universe and join the Spider-Gang in the battle against the Kingpin's forces following the death of the "local" Peter Parker.
In Chapter 99 after a large meeting between Jedi and Avengers, Thor speaks of the barrier that surrounds and isolates the galaxy from the rest of the Universe weakening. He states that the rest of the Universe will soon become aware of this and while good may come from the outside, evil comes with it such as the Yuuzhan Vong and Thanos and many other cosmic dangers.
Chapter 109 had a small teaser trailer of small, possible events to come. One of great interest is the possibility or now likeliness of Barriss learning under Dr.Strange, Mordo, Wong and Celeste and becoming a Jedi Sorceress.
Piggybacking off the trailer in Chapter 109, 110 is an entire chapter solely dedicated to being a trailer to set up all that's to come of Season 4.
Chapter 113 had the Guardians of the Galaxy and the Mandalorians talk about the power vacuum in the Outer Rim, likely meaning that there's gonna be conflict in that region of space with multiple crime organizations and groups vying for power.
Plus, it appears the Punisher has already started his one man war against crime, meaning he's either gonna run into the Guardians soon or the Avengers but it is likely the former.
