Facial hair can interfere with the seal of a facemask, effectively rendering it useless. Here are illustrations (with unintentionally hilarious titles) from the CDC showing the facemask compatibility/incompatibility of different facial hairstyles.
Since the given names are worthless at helping you quickly find your choice of on-face pompadour, we've broken the chart up into more sensible categories.
Hair on Chin, Good
Hair on Chin, No Good
Hair on Chin, Marginal
Mustache Only, Good
Mustache Only, No Good
Mustache Only, Marginal
My hat's off to the healthcare workers who have to navigate both facial grooming and regular mask-wearing! If I had to do it daily, I'd go clean-shaven.