The poster for the film shows a picture of a red hat with the slogan "The First Purge." This is a reference to President Donald Trump's red "Make America Great Again" hat which was used throughout his presidential campaign.
The trivia items below may give away important plot points.
Nya (Lex Scott Davis) barely escapes from being pulled into a floor grate, and refers to her attacker as a "p#ssy-grabber", a clear reference to one of Donald Trump's controversial remarks prior to becoming President.
Despite the fan theory and speculation that President Charlene Roan (Elizabeth Mitchell) would be assassinated in this film leaving Minister Edwidge Owens to ascend into the presidency and for the annual purge to resume. This theory was proven to be false once it was revealed that this film would be a prequel. Since this film is in fact a prequel in The Purge saga, Charlene Roan can't be assassinated. We last saw her in The Purge: Election Year, having survived at leasts 18 annual purges. The end of that film showed her to have succeeded in becoming president.