6-3 per curiam dismissal for lack of standing, with Breyer, Sotomayor, & Kagan dissenting (get used to that). The plaintiffs can re-file their case & appropriately litigate the merits once there's a live case/controversy, but given that Census data delays mean that presidential approval of the apportionment isn't able to happen 'til after January 20th, Biden will just end up mooting the case by having the Census Bureau re-do the apportionment with undocumented residents included in the count.
Which just goes to show that the liberal wing can be political also. Clearly they are angling to give Trump one more humiliation as he heads out the door. But also, the case is not yet ripe.