Commander Lilith & the Fight for Sanctuary will be available for free to all owners of Borderlands 2 and Borderlands: The Handsome Collection until July 8 at 06:59:59 UTC (11:59:59 PDT). Requires Borderlands 2 or Borderlands: The Handsome Collection to play.
Link to steam store: https://store.steampowered.com/app/872280/Borderlands_2_Commander_Lilith__the_Fight_for_Sanctuary/
https://www.youtube.com/watch?v=VjRp1BkP1ZI
Edited