Chicago is one of the flatter major marathons. The grade adjustment barely moves the pace, which is the point: if your band and a flat pace chart disagree by much, the goal time is doing the work, not the hills. Wind off the lake is the variable a course profile cannot see.
What to use the band for
Even effort stays close to even pace. That is a fair way to run a flat marathon.
A negative split still starts a little easier if you want the second half faster.
A conservative start keeps the first 3 miles from becoming the fastest of the day.
The few feet of rise in this profile are approximate. Check the current course with the race organizer. $7 unlocks the printable band, the CSV, and three alternate goal times after the free 5 miles.
Course Pace Band is a pacing chart, not a prediction that you will run the goal time, and not medical advice. Preset elevations are approximate planning profiles, not a survey. A GPX file is only as good as its elevation track. Heat, wind, and crowds will move the clock.