Arrests by Immigration and Customs Enforcement (ICE) were up in 2017, but not as dramatically as you might think. What has increased is the visibility of these arrests and the fear that they bring. It is generally believed, without only scant evidence, that undocumented immigrants are leaving the US in large numbers. This would continue a downward trend which started in 2007.
Some people might cheer this action, but as a whole the economy probably isn’t. Undocumented workers do jobs that no one else wants to, for the most part. Their absence means that work is not being done and wages are rising rapidly in areas that have depended on cheap labor for years. There may be signs that this is accelerating and will ultimately spark a high rate of inflation and even shortages.