The US Supreme Court is considering whether to take cases where the issue is whether a search warrant or a mere subpoena is necessary to obtain historical cell-site data.
Links to the multiple petitions for cert can be found here.
And an argument for revisiting the third-party doctrine is here. As previously noted, the Oregon Constitution provides much greater protection to records held by third-parties, per State v. Ghim. Having said that, the exact parameters of that protection will continue to be unknown until defense attorneys start preserving the issues.