On Friday, June 22, the Supreme Court issued its much-anticipated opinion in Carpenter v. United States, holding that a warrant is required for police to access cell site location information from a cell phone company—the detailed geolocation information generated by a cellphone’s communication with cell towers. As predicted, Chief Justice Roberts authored the majority opinion, reversing the Sixth Circuit’s decision. He was joined by Justices Ginsburg, Breyer, Sotomayor and Kagan. The remaining four justices, Justices Kennedy, Thomas, Alito, and Gorsuch each filed separate dissenting opinions.
There has been a ton of coverage about this in the US. As per usual, Lawfare does a great job of reviewing this without hyperbole. Give it a good read as it has far reaching potential implications.