In addition to what was already said above, there was a post in a reddit forum about road racing near Chicago just a couple of weeks ago, so you might find this helpful as well:
There’s a lot of road racing options in and around Chicago, once it finally warms up. Time Trials are fewer and further away from the city proper, and there is a healthy CX scene that you can race almost every weekend from September through November with deep fields - especially in the lower categories.
There are many clubs in Chicago, each with varying degrees of size and competition focus. xXx Racing is probably the largest, but there are others to chose from. https://xxxracing.org/
Winters here are certainly rough - with the weeks-at-a-time temps of -6C highs and the limited hours of daylight once the time changes (in early November through early March the sun sets at 4:30 pm) outside riding becomes a challenge. However, since you’re likely a loyal TR user, you will probably be used to the indoor riding requirement. Group rides on the weekend are well attended and have varying degrees of organization, but there’s almost certainly a group that you can find to match your aims for the day.
Finally, ALL route options around here are extremely flat. As in, 609m of elevation gain in 180km flat. There are, however, plenty of opportunities to ride up a “Belgian Mountain” on particularly windy days. Depending on where you live, route options can be a bit limited for training, and unless you’re living somewhere in the suburbs it’s pretty hard to get completely “out” of the city. In my opinion, the city has great infrastructure for commuting/traversing the city.