The show takes place in the same world as Entourage.
Eli Gold is based on Rahm Emanuel, just as Ari Gold is based on his brother Ari Emmanuel. Obviously Eli and Ari are brothers, and the two shows take place in the same universe. The show is heaven where the cast of The Wire are rewarded with a universe where the law is less corrupt.
It would explain all the familiar faces. After the show finishes, Peter ends up (back) in prison
Probably got corruption, since the DNC was said to be getting ready to throw him under the bus after his failed presidential bid. Which explains why the Florricks get hardly a mention in The Good Fight as he's well and truly out of the Chicago political scene and Alicia is damaged goods as a result. This in turn causes Eli to either lie low or move to another part of the States, which is why he's hardly ever mentioned in said aftershow despite his daughter being a major character.