From the organizers:

In spite of our efforts, we are at the mercy of the Illinois Government to approve the January Show. These are indeed unprecedented times, but in a rare turn of events, the AHR Expo has been presented with the opportunity to change the 2021 Show dates at McCormick Place. The offered dates are March 15 – 17, 2021 and by possibly moving the Show 7 weeks later into 2021 we are optimistic that this would give the AHR Expo the best chance to hold the most safe and successful Live Event possible.   

ASHRAE and AHRI are studying the viability of these dates, recognizing that the date change is dependent on the support of our Exhibitors and Visitors.