Trump has not said much about LEGAL immigration, yet, except the same bromides that he loves legal immigration. There have been people speaking about this immigration nightmare going all the back to the late 80s. Trump caused a firestorm because we have been getting blasted on this issue by the GOPe & the left.
The illegal immigration nightmare began when none other than Carter was President. Reagan attempted to stop it, but dims did not follow through on enforcement after the amnesty (the enforcement they agreed to in order to get amnesty they claimed were unfair, inhumane...) and it has become progressively worse.