DACA, the Deferred Action for Childhood Arrivals, was an executive order - not a law - signed by then President Obama with his pen and his stool in 2012 that made illegal minors low-priority for deportation and made them eligible for work permits. 741,546 applicants have been accepted (you have to register) as of June 2016. According to Wikipedia, so about as accurate as a coin toss, about 10% of these "Dreamers" have found work, taking jobs away from US citizens, including poor minorities and legal immigrants who had to jump through hoops in a process that can last over a decade, but very few have gone to school.
DACA is not a law. It failed to pass through Congress, so Obama said "I have a pen and I have a stool so I'm going to write an executive order and the rule of law can go pound sand." And that's what he did.
Today, after five years, President Trump used his own pen and stool to eliminate DACA, but gave Congress a six month window to save the program. Since Congress has done precious little in these past six months, so will they just kick the can down the road until the Dems take more seats, will they extend DACA into a full-blown law, or will they do the legal, constitutional, moral thing and kill this attempt at Democrat ballot stuffing? I have about as much faith in Congress as I have in Chuck-E-Cheese being a real human-sized singing rat entrepreneur, so I don't expect them to either follow the law, do the right thing, or even get off their asses and work for a living.