One of Overwatch's annual special events, the Winter Wonderland, is making a comeback this year according to Twitter post by @OverwatchES. In the teaser trailer of the event, Mei's weather-modification drone emits snow on top of some eggs under a Christmas tree. The video ends with the dates of this event: Dec. 15, 2020 to Jan. 5, 2021.
Historically, Winter Wonderland includes two new co-op brawl modes:
• Mei's Snowball Offensive
It brings players to a reskin of Ecopoint: Antarctica and the Black Forest. This is an Arcade game mode that temporarily replaces the mode All Brawls! during the event period. Each team has six members and players can only play Mei with a modified version of her standard gun.
• Mei's Yeti Hunt (since 2017)
It takes place in Nepal Village (Yeti Hunter) map. It is a 5-v-1 game with five Meis hunting down Winston (who poses as the "Yeti").
Sometimes, there is a seasonal change in rule for Mystery Heroes game mode called Winter Mystery.
The Christmas-based event also previously contained Winter temporary reskins of several maps such as Hanamura and King's Row, special achievements, and a limited series of items. These items include skins, emotes, victory poses, voice lines, sprays, highlight intros, and player icons. Event-exclusive content usually becomes unobtainable once the event ends.
There is no details yet on the rewards for this event yet during the time of writing but surely fans cannot wait to shoot snowballs and collect the event-exclusive loots in-game!