Shortly after Apex Legends Season 3 dropped (which is amazing btw), Respawn Entertainment is gearing up for a special Halloween event called Fight Or Fright. This is a collection event with a limited-time mode called Shadowfall, which is a nighttime version of Kings Canyon (the old map).
Along with the old map coming back, you can earn exclusive legendary weapon skins. There are 24 cosmetic packs that can have 24 limited premium cosmetics that players can unlock by either: direct purchase, unlock with crafting materials, or event apex packs.
Take a look at the blog for the full details on the Shadowfall game mode, a preview of some of the weapon skins, and some of the Halloween skins you can earn during the event.