From March 3-17, Apex Legends will host a new event called "Déjà Loot Mode". During that time, the 'legends' will have to adapt to changing conditions for two weeks because there will be fixed loot placed on the map (so you have to remember where you can get the important attachments/weapons and be there before your enemies arrive).
Once a day the item layout changes and in the second week the map changes as well, which means a return to iconic Kings Canyon. In addition to cosmetic items and in-game challenges, a so-called 'Evo-shield' is introduced with System Override, which becomes more and more powerful according to the damage dealt while wearing it.
You can read more about System Override over at EA, but before you go there's a trailer to watch below.