What happens right now is this: ICE can run loose and do whatever they want. If some judge finds their activities illegal, they can block ICE from doing the illegal things.
But...who's going to stop them? Not the DOJ. Stephen Miller has said that ICE have "federal immunity". The keen observer will of course know that there's no such thing as "federal immunity", so a charitable way to interpret that statement is that no-one federal will go after them.
So what about states, and local police? Sure, they could start arresting them, but then again, Miller et. al have warned the states about not interfering, threatening with going after LEO's etc. with federal charges if they do so.
The long story made short is that they can (and will) keep doing illegal shit until someone stops them, and that's not going to happen as long as Trump is POTUS. DOJ and ICE leaderships has explicitly said that their workers should just ignore the law and courts.
The scary thing is that there is.. you should look up "sovereign immunity". The government has complete immunity, except where and how the law permits it to be held accountable. And while we have a constitution, defending those rights through the courts requires legislation to permit it. For the most part, federal law permits lawsuits against states that violate the constitution, but have permitted far less accountability for federal actions that violate the constitution.
For example, Section 1983 of the Civil Rights Act only permits individuals to sue state and local governments for rights violations. It can't be used to sue the federal government.
There's many court cases, dating back decades, tossing out cases against the federal government for rights violations. Look how SCOTUS has limited the precedent set by Bivens over the years, basically neutering it entirely.