The War of the Chosen - Tactical Legacy Pack Add-on for XCOM 2 has 8 achievements.
Complete the 'Blast From the Past' legacy operation with a gold medal
Complete the 'It Came From the Sea' legacy operation with a gold medal
Complete the 'Avenger Assembled' legacy operation with a gold medal
Complete 'The Lazarus Project' legacy operation with a gold medal
Complete a random legacy operation
Complete a Skirmish Mission
Complete a Local Challenge
Complete a single player campaign with Tactical Legacy Pack content