After the season 2 finale, almost the entirety of Peacemaker season 1 is still canon in the DCU. Everything except the Justice League. The first episode of season 2 notably replaces the League with the Justice Gang, first seen in Superman. In addition, Peacemaker and the Justice Gang later reject each other during Chris's audition for the team, paving the way for the 11th Street kids to instead found Checkmate. And let's not forget the OG team that led to the formation of Checkmate in the first place.
For now, it's unclear exactly which parts of The Suicide Squad are canon to the DCU. We don't even know if fan favorite Harley Quinn will return as a canon character, but throughout Peacemaker season 2, Chris's arc has been driven by how he killed Rick Flag Jr. in the Suicide Squad and how Amanda Waller's agents rebelled against her to save the world. With Waller set to star in her own DCU series, this actually connects to these next elements that Peacemaker confirms as canon.
While these infamous prisons don't appear in Peacemaker season 2, Rick Flag Senior confirms that they exist in the DCU. Specifically, during his pitch for Planet Salvation to the US government, Flag mentions how neither Arkham nor Bel Reeve are capable of actually securing metahuman offenders who escape their cells on a regular basis. And in their different iterations in the comics, movies, and TV shows, these prisons house criminals such as Harley Quinn, Deadshot, King Shark, Captain Boomerang, Black Manta, Lex Luthor, and the Joker.
In any case, with the Peacemaker season 2 finale teasing Planet Salvation, the DCU is bound to revisit the deadly residents of both Arkham and Bel Reeve very soon. That said, this next Easter egg may be even more crucial to what's considered canon in the future. The finale sees Chris and Amelia eating and drinking at Big Belly Burger, which is also where Bordeaux gets recruited by Amelia. And Big Belly Burger isn't just a recurring restaurant chain in DC Comics continuity. It was also heavily featured across the CW's Arrowverse, not just in Arrow, but also in the Flash and the animated web series Vixen. In short, Big Belly Burger could be a hint that certain parts of the Arrowverse could become DCU canon soon, maybe even in chapter 1, Gods and Monsters. It's certainly an indication that Gunn hasn't forgotten the Arrowverse.
And finally, there's one last thing from the DCEU that's still considered canon after Peacemaker season 2. Notably, Peacemaker season 2 makes no connection to Blue Beetle, aka Jaime Reyes, whatsoever. However, there's also nothing in season 2 that negates what James Gunn said about Blue Beetle being canon. In fact, the animated Blue Beetle DCU series is still confirmed to be in development. So, did Peacemaker season 2 leave behind any other clues about which DCEU elements are now canon to the DCU? Tell us your thoughts in the comments and thanks for watching Screen Rant.