Arrived from LHR to Chicago a few days ago and they had just opened a fast track combined immigration and customs for anyone without checked baggage. The main immigration hall look chaotic, however I got through the new channel and landside in less than 5 minutes. Perfect!!!!
Don’t know at which other US airports this new service is available but a very welcome addition.
BTW I was traveling on UK passport under visa waiver and was able to use this new channel.