Chicago PD has been occasionally frustrating in season 12. The show has introduced fascinating character arcs for several of its veteran presences, but the emphasis on case of the week stories has led to some of these arcs being pushed on to the back burner. There are times where the underlying feelings of the IU members are not even referenced.
We do, somewhat, understand. There's been some excellent standalone stories in season 12, as well as a crossover event and an ongoing conflict with Chief Deputy Charlie Reid (Shawn Hatosy). We are excited to what happens with the villain, but we're relieved to have confirmation that the season 12 finale will place the emphasis on character over story.
Gwen Sigan promised to focus on Burzek's wedding

Chicago PD showrunner Gwen Sigan confirmed that the May 21 finale (which is a two-parter) will not only continue the rivalry between Reid and Hank Voight (Jason Beghe), but deliver on the emotional arcs that have somewhat gone by the wayside. We're thinking, primarily, about the wedding of Adam Ruzek (Patrick John Flueger) and Kim Burgess (Marina Squerciati).
There was a reference to the Burzek wedding the last time Burgess led a season 12 episode, "Seen and Unseen," but for the most part, you can comb through the show and find surprisingly very few references to the fact that two of PD's main characters are going to tie the knot. We wish there had been more attention paid to them in the lead up, but Sigan promises the wedding will be a central focus.
The finale will further Voight and Chapman's relationship

There's also the burgeoning (potential) romance between Voight and ADA Nina Chapman (Sara Bues). Once again, we're dealing with characters who have had a great deal of screen time together, despite refusing to address the fact that Chapman voiced having feelings for Voight. "Chapman grows closer to Voight [in the finale]," Sigan told TV Line, bringing a long sigh of relief to anybody who wants to see these two end up together.
On a smaller but simultaneously important scale, the two-part finale will explore the "emotional fall out" of Dante Torres (Benjamin Levy Aguilar) and his season-long struggles. The character has had a difficult time coping with the death of CI Gloria Perez (Yara Martinez), and the ways in which Reid has been able to use said death to blackmail the IU. He's carrying around a lot of guilt, to the point where he is suffering from insomnia.
He opened up to Voight about his struggles in the aptly titled "Demons," but Gwen Sigan promised that we will see Torres makes additional strides in an effort to remain part of the IU. We'd rank it third behind the Burzek wedding and Voight/Chapman romance, but it's still something we are glad to get additional time on.