James Gunn says he knows whose story is being told in the current DCU, and it's not who we might expect. Speaking to ScreenRant, Gunn has explained that, much like he felt his Guardians of the Galaxy trilogy was ultimately about Rocket's journey,

This seems to confirm that Peacemaker is the bridge between the old DC cinematic universe (sometimes called the DCEU) and the new DCU. Peacemaker Season 2 will take place after the events of Superman and will feature cameos from Frank Grillo, Nathan Fillion, and Isabela Merced, reprising their roles as Rick Flagg Sr., Guy Gardner, and Hawkgirl.