SCOTUS could have denied cert to the same effect. Maybe they intend to reverse, to allow the exec to define "take care" in the Exec's terms. Maybe they will spank Congress. Maybe some combination, as they did in Youngstown, although in this case, on how the branches (lower courts, in particular) should deal with disputes that arise out of inaction rather than positive action.
Then they can either render a ruling, or send the case back down for a decision in accordance with the principles set forth.
I am not even clear on the procedural posture. Right now there is just a TRO, I think. This can go around and around for a couple more years. Lawyers and judges getting rich while the invaders are free to enter as they please.