In April 2020, Trump announced a 60-day memorandum on immigration.

The order was limited to would-be immigrants living outside the country seeking a green card. It had some significant exceptions, like for the spouse or child of a citizen, military service members, and medical professionals. It did not affect anyone already within the United States.

Supporters of further immigration controls regarded the provisions as too limited, while immigration advocates worried that the 60-day period and those affected could be easily expanded.

A month after the order, the administration announced an expansion in an attempt to retain more jobs for citizens in the wake of COVID-19. The new regulations banned entry on certain visas through rest of the year, including including high-skilled H-1B visas. The order also had exceptions for agricultural, healthcare, and food industry workers.

Time – President Trump Has Blocked New Legal Immigrants. Here’s Where Else He’s Clamped Down on Immigration During the Coronavirus Outbreak
NBC News – Trump halts immigration for 60 days. Here’s what the president’s order means.
Texas Tribune – Trump signs order pausing immigration for 60 days, with exceptions
Los Angeles Times – Trump announces new visa restrictions on immigrant workers but exempts agriculture, food service, health