Yes, there is such a thing as a Chicago Republican Party… and the party there has decided not to endorse incumbent GOP governor Bruce Rauner in the March primary. Instead the organization is backing Rauner’s challenger, state Representative Jeanne Ives.
The Illinois Review website says it’s very unusual for a regular Republican party organization to fail to endorse a sitting governor of that party… and notes that while Republicans are outnumbered by Democrats there, Chicago Republicans provide up to five-percent of the total statewide GOP primary vote.