Subject: A place to concentrate the deportees
Trump Says U.S. Will Hold Migrants at Guantánamo

The president suggested the United States would prepare to detain tens of thousands of migrants at the U.S. Navy base. It was unclear how the plan would take shape.

I guess you could call it a concentration camp.

In addition to the cost of these operations, there is the lost labor and tax revenue from these workers.

"Tens of thousands" is still quite a ways from the 11 million he promised to deport.