Almost uniquely in the US there remains a mask mandate in the New York airports (not Newark NJ) due to the Port Authority interpretation of current NY state public health guidance. I would say it was about 60% observed in T7 and T8, 20% in the lounges.
That expires when you board the plane.
It is enforced with loud threatening automated announcements every ten minutes citing that "it is a federal requirement that..." which isn't the case.
I think there remains a mandate at LAX as well.