The tease from Deadpool 2, although as the rights to the character belonged to Fox at the time, the two movies were kept separate from the wider Marvel continuity.
With the rights to numerous characters now having reverted to Marvel, Deadpool is set to make his MCU debut in Deadpool 3. Exactly how Deadpool will work in the MCU remains to be seen, but the prospect is exciting. In the comics, the character is a regular collaborator with numerous other heroes, and his fourth-wall-breaking antics are enough to bring some levity to the stories of even the most serious characters.
Deadpool 3's writers Paul Wernick and Rhett Reese have teased story details that evidence how the film will perfectly introduce Deadpool into the MCU. Wernick and Reese described Deadpool 3 as a "fish-out-of-water" story, explaining that it will "drop a lunatic into a very sane world." Not only does this perfectly match Deadpool's role within the Marvel comics, but it also affords a clear opportunity to double down on the elements that made Deadpool and Deadpool 2 so successful.
How Deadpool Can Fit Into The MCU
The story details from Deadpool 3's writers prove not only that the general tone of the previous movies will remain intact, but also that Deadpool 3 won't dive too deep into serious exposition. Describing the sequel as a "fish-out-of-water" story seems to indicate that the film will have Deadpool somewhat confused or overwhelmed by his sudden introduction into the MCU, and he will likely continue his fourth-wall-breaking ways in order to address the change. This allows for an important continuity between Deadpool but also leaves the essence of the character intact.
With many other characters, carrying over a previously separate hero into the MCU can be difficult and messy. This much has already been evidenced by Kingpin's appearance in Hawkeye, which came with many complex questions regarding continuity that have still yet to be answered. Having a more self-aware hero fill a "fish-out-of-water" role within the MCU erases the need for such questions, as it seems that Deadpool himself will address that confusion, thus diffusing potential for issues by making it a less serious affair.
Ultimately, the tease of what Deadpool 3's story will entail is an excellent sign for the sequel. It shows not just that the film will finally introduce the character into the wider franchise of the MCU, but that the writers understand the appeal of Deadpool as a character. By allowing him to fulfill a more self-aware role within the MCU, he not only adds some additional levity to the franchise but also helps Disney avoid an obvious error with Deadpool 3 by having him become bogged down by messy continuity issues. The very nature of the character and the fact that this will seemingly remain intact will allow Deadpool 3 to simply mock any such questions, making the character's induction into the MCU yet another opportunity for Deadpool to hilariously break the fourth wall.
