Reverence is an interesting concept in relation to geek properties. Wherever there is fandom there is an army of fans expecting their favorite property to be treated with reverence. But, what if your geek property is founded on irreverence? Enter Deadpool: a character built on being an irreverent bastard juxtoposed against an ensemble of serious credible actors. So Deadpool and Wolverine poses an interesting conundrum for the MCU. More than perhaps any other franchise the MCU is, if not founded upon, developed through reverence. Reverence for its source characters, its prior cinematic successes, and certainly its canon. The somewhat self-aware naming of its own universe as "The Sacred Timeline" not so subtly winks at this. This self-reverencial foundation is critical to the MCU's success. Each film must serve to advertise every other film and all of them must exist in an aesthetically, and tonally coherent universe. The very concept of this mutually supportive system of films is threatened by the existence of a character whose purpose is to challenge the credibility and value of his peers. So the entry of Deadpool into the MCU forces the creatives behind Deadpool and Wolverine to answer the question: "How do you maintain the MCU's self-reverential foundation while spotlighting a character founded upon irreverence for his surroundings?"
The solution the filmmakers landed on was simultaniously quite clever and cowardly: set the film in a garbage bin. I mean this almost literally. The bulk of the film takes place in a Mad Max-esque wasteland populated by the orphans and rejects of Disney's corperate conquests. Some of the characters from the late 20th Century Fox's Marvel superhero movies: Chris Evans's Johnny Storm, Wesley Snipe's Blade, and even Channing Tatum's Gambit (which never managed to make it to screen), make up the bulk of the supporting cast of this ostensibly "MCU" movie. This premise gives the impression of giving Deadpool a sandbox to play in so that he can't really ruin the MCU while giving him other targets for his irreverence.
To be honest, they needn't have been so cowardly. Despite Deadpool's irreverence being on full display, earning the movie's R rating, the target is rarely specific Marvel films or characters. Aside from one throw away line about the MCU not being in a great place right now, I struggle to remember a single irreverent quip targeted at a marvel character or film. In fact the MCU is still directly referred to as "The Sacred Timeline" (a term that Deadpool, the character and the film, lets pass without irony) and it's Deadpool's goal in the film to become an Avenger (again wtihout a shred of irony). This stands out as especially odd given the first two Deadpool movies make a point that Deadpool doesn't want to join the X-Men because he they would place limitations on his activities that he would be unwilling to accept. There is an inherent irony here that Deadpool's entry into the MCU, by locking him in a trashcan for most of the movie is placing limitations on his activity. These restrictions extend even beyond protecting the value of the MCU specific brands: even the Fox movies are treated with a great deal of reverence. Everyone has a moment of teary-eyed silence for the ending of Logan. All the Fox characters do die, but are given heroic sacrifice deaths, and plenty of badass moments to please their fans. The only character I can remember being belittled or sidelined for comedic effect was Chris Evans's Johnny Storm, and even then this was done at the hands of the villain with neither Deadpool nor the movie itself directing any serious jabs at the character. The only other possible counter argument that I remember is the opening action sequence where Deadpool desecrates Logan's grave from the movie Logan (2017) and uses his skeleton as a series of weapons to take down TVA agents. Perverse as it is, this is also a form of reverence. One of the most fondly remembered aspects of the movie was its R-rated, uncompromising, brutal violence. Which is almost eulogized by the R-rated brutal violence of the opening credits. It is also worth noting that the first two Deadpool movies established a gag wherein the opening credits would themeselves irreverently insult the cast and crew of the film. The first film had credits like: "starring a gratuitious cameo" and "produced by asshats", while the second film replaced the credited names with Deadpool expressing disbelief over, and berating the filmmakers for the death of his girlfriend. Deadpool and Wolverine was, presumably, unable to carry this gag forward as the credit text was quite standard.
Ultimately, the film just winds up being a fun, albeit toothless, superhero satire. It does what every Marvel movie is supposed to do: reinforce the value of its associated brands while being entertaining enough to pass a 2 hr. runtime. I don't mean this to be a condemnation of the film, but rather a kind of weary praise. It's a worn out trick executed with passion and craft, and that really seems to be the best a Marvel movie can aspire to be.