Lower courts had invalidate the Congressional district in two states because they heavily favored Republicans. But the Supreme Court has blocked the rulings in Michigan and Ohio. From:

“In the Ohio case, a three-judge panel ruled unanimously earlier this month that the district map draw up by the Republican-controlled legislature unconstitutionally discriminated against Democrats. “We are convinced by the evidence that this partisan gerrymander was intentional,” the ruling said.”

The Court set aside the rulings because of similar cases they’ve already taken in other states. From Politico:

“The Supreme Court already heard arguments in partisan gerrymandering cases from Maryland and North Carolina — and the high court is expected to render a decision next month that could decide what happens in Michigan and Ohio as well.”