President Trump issued a last-minute extension of the presidential proclamation which prevented visa approvals and entrance for a large number of potential immigrants. The extension means that this ban would continue through the end of the president’s term in office and it would be up to the Biden Administration to rescind it before the new deadline, March 31, 2021.
The original proclamation which is being extended is Proclamation 10014 of April 22, 2020. This sweeping proclamation suspends the entry of immigrants to the US. Combined with other proclamations and executive orders, perhaps millions of immigrant family are awaiting their turn for visa interviews and actual visas to be able to enter the US.
The ban also impacts many employment-based green card applicants, but primarily only those who are currently outside the US. This proclamation does not restrict nonimmigrant visas, but some categories of those are also covered by other suspension proclamations.
Furthermore, interviews in many countries are still delayed or halted completely due to the pandemic, which has forced the closure of many embassies and consulates. The US Department of State recently posted an update about how those posts would handle reopening.