USCIS recently posted the following updates relating to policy on facial coverings:  USCIS Response to COVID-19 

• Everyone 2 years of age or older who has not been fully vaccinated must wear facial coverings.
• A person is considered fully vaccinated two weeks after receiving the last recommended dose of vaccine.

AILA notes that although the USCIS website still notes that a person with a temperature of 100.4 F or higher must leave USCIS field offices and asylum offices, in some field offices temperature checks are no longer being conducted prior to entry.

Please also be advised that local mask mandates may still be in effect. Please check for the city and state rules in the location of the USCIS field office. For the latest USCIS guidance on precautionary measures relating to COVID-19, please visit: https://www.uscis.gov/about-us/uscis-response-to-covid-19