NextNav Inc. (NextNav) filed a petition for rulemaking requesting that the FCC initiate a proceeding to reconfigure the 902-928 MHz band (Lower 900 MHz Band) and adopt new rules to enable the deployment of a 5G terrestrial positioning, navigation, and timing network.

This proposed allocation would make radical changes to the band and reduce or eliminate to the ability for hams and Part 15 users to utilize 900 MHz in many (most?) ways.  

This post by N1WBV in Massachusetts explains it. Consider reading up and filing comments with the FCC:

Despite several articles in telecom and legal trade publications, I have yet to see any comment from the ARRL on the matter.  Hopefully they are planning on addressing this with their membership soon as the deadline to submit comments is Sept. 5.