First, in Gill v. Whitford, a much-watched case challenging Wisconsin's recent re-districting.
Despite much hope to the contrary, the Court didn't really reach the merits. Instead, they held that the petitioners, a group of Wisconsin voters, lacked standing. However, there is still hope that we could get an actual ruling on the issue down the road.
First, the majority noted that the plaintiffs had not really alleged personal injury to themselves, instead describing a statewide injury that was simply too general. In addition, the majority pointed out that prior rulings on this have been a bit murky over the years. In addition, a concurrence by Justice Kagan stressed the harm of gerrymandering, and emphasized that the courts are really the only branch that can do anything, given the nature of the problem.
The other bit of silver lining is that the Court didn't dismiss the original claim (which would usually be the response to failing to show standing). Because this is a blurry area, the case was sent back to the district court to give the plaintiffs a chance to show individual and particularized harm.
One more interesting thing, from a comment by Kevin Russell, one of the writers for SCOTUSblog:
As always, the wheel turns slow, but it turns.
Meanwhile, we also have Benisek v. Lamone, a similar case filed against the state of Maryland by Republicans. They asked the Court to decide on the merits, i.e. whether Maryland's congressional districts unfairly advantaged Democrats. They requested a preliminary injunction, which would have forced Maryland to use the old map. This was denied. However, by this time, the Gill case had already been taken up by the Supreme Court, and so the lower court in Maryland stayed further proceedings until SCOTUS made its decision. The plaintiffs appealed the denial of the injunction. SCOTUS rules, per curiam, that even if plaintiffs had shown that they were likely to prevail on the merits of their case, the "balance of the equities" was against an injunction. One major issue for the court was that the motion for the injunction wasn't filed until way after the original lawsuit.
So this one too isn't dismissed, and will still have to go forward without much guidance from the decision in Gill.
I do wonder if part of the reason for Justice Kagan's concurrence in Gill, emphasizing the severity of the harm and that the courts have to be the one to fix it, wans't an attempt to give the lower courts something to go on. Still, she would know as well as anyone that any ruling on those cases is going to end up back before SCOTUS.