To reduce the spread of COVID-19, USCIS temporarily closed their public-facing office on March 18th. However, they recently announced they will be extending these closures until at least May 3rd, 2020.
They are still accepting documents through mail, but any face-to-face interactions such as immigration interviews have been postponed. If you had an interview scheduled before May 3rd, please reach out to your Hacking Immigration Law attorney or paralegal for guidance.
You can read the full notice from USCIS here: https://www.uscis.gov/about-us/uscis-response-coronavirus-2019-covid-19