The Supreme Court of the UK has handed down judgment in the Shamima Begum case - see judgment dated 26 February 2021 -  UKSC 7. - Lord Reed PSC, Lord Hodge DPSC, Lady Black, Lord Lloyd-Jones and Lord Sales. The judgment is unanimous.
The Supreme Court's webpage about the case is HERE and a Press Summary is available.
Earlier court decisions:
The main SIACjudgment is Shamima Begum (Preliminary Issue : Substansive)  UKSIAC SC_163_2019, while there is also a brief High Court judgment refusing a linked application for judicial review:  EWHC 74 (Admin).
Commentary: FreeMovement 7 February 2020
Court of Appeal (July 2020) -  EWCA Civ 918 - King, Flaux and Singh LJJ.
Commentary: Free Movement 16 July 2020.