In January 2024, in End Citizens United PAC v. FEC, a divided panel of the U.S. Court of Appeals for the D.C. Circuit concluded that the Federal Election Campaign Act does not create a cause of action to challenge the FEC's exercise of enforcement discretion.
In October 2024, the full court voted to rehear the case en banc (as I noted in this post). Interestingly enough, the grant of rehearing expanded the issue before the court, perhaps for the purpose of cleaning up circuit precedent in this area.
Oral argument was held in February 2025.