Sidney Earl Swanson claims the track Chicago, from Jackson's recent Xscape album, is a rip off of his own 2002 tune, Come Home On the Move. Swanson has sued Timbaland, Cory Rooney, MJJ Productions and Sony Music. Swanson claims "Defendants copied and incorporated substantial, original portions of the infringed composition in (Chicago)."

I was able to get the complaint document. You can read the document here : https://www.scribd.com/doc/242409400/Chicago-Copyright-Complaint

As a short summary 

- Swanson's "Come home on the move" song was created in 1995 and registered in 2002.

- Copyright registration refers to it as "music only"

- Complaint alleges the infringed material is "composition" 

- Timbaland and Rooney is being sued as they are credited as the producers of the song "Chicago"