On January 21, the U.S. Court of Appeals, D.C. Circuit, held oral arguments in Common Cause v Biden, a challenge to the filibuster. According to this story, the three judges seem overwhelmingly likely to reject the lawsuit. Thanks to Rick Hasen for the link.
I am certainly sympathetic to the complaint, but it is a hard one to make in the face of the political question doctrine and standing requirements. Best of luck though. One never knows.