Marvel Rivals' Path to Doomsday - Avengers: Endgame mode began Oct. 24 UTC and is scheduled for limited sessions across four consecutive weeks.
The mode's first three windows on Oct. 24 have passed. Marvel Rivals says it will return for limited times in each subsequent week, with the exact schedule posted on the official patch page.
Players can earn the Captain America: The Winter Soldier costume and other rewards for free. The broader event runs from Oct. 22 at 9 a.m. UTC through Nov. 26 at 9 a.m. UTC, but that event window does not mean the mode is playable continuously.
See the Marvel Rivals Oct. 21 patch notes for the official mode schedule.