The Coalition, the team behind the popular Gears of War franchise, are launching a special “Gearsmas” celebration to ring in the snowiest time of the year. If you’re wondering what Gearsmas entails, we’ve got a rundown of the various aspects of the event. Below, you can watch Xbox’s video showcasing some of the content.
The best part of any festive celebration, at least in a video game, is the stuff: the items you get to celebrate with and shoot into your enemies’ faces.  Gearsmas brings with it a special Festive Collection with some new character and weapon skins.  As Adam Fletcher from The Coalition writes,

The Gearsmas Pack is full of Holiday Presents with 28 pieces of unique content to collect. For 400 Credits, each pack contains One Bounty and two items from the Gearsmas collection listed below:

• 3 ‘Ugly Gearsmas Armor’ Characters – JD, Kait and Swarm Drone
• 4x Gingerbread Weapon Skins
• 4x Festive Tree Weapon Skins
• 4x Snowman Weapon Skins
• 4x JD Wrapping Paper Weapon Skins
• 4x Kait Wrapping Paper Weapon Skins
• 4x Swarm Wrapping Paper Weapon Skins
• 1 Commemorative Gearsmas Emblem

While still on the branch of in-game items, there will also be time-limited daily rewards for players to scoop up and unwrap. One December 16, there will be a special Chuzzmas Emblem and on December 27, there will be an Ice Boomshot gun to be had, so be sure to log in to get that loot.
While themed items are always nice during this festive season, The Coalition is introducing a new multiplayer mode called Snowball Fight. Just like the real thing, players begin the match with a new weapon called the Snowshot and two Snowballs, the Snowshot’s ammo of choice. And when you’re out of Snowballs, there’s more to pickup across the map to keep the fight going.  Crossplay Versus is also returning as part of the Special Event playlist meaning that Windows 10 players can team up with their friends on Xbox One (and vice-versa, don’t worry) in squads of up to five players to rip the enemy a new one during Gearsmas. Both playlists will also net players 1.5 times the experience points, so now you have another reason to stay out of the cold and play Gears.
Rounding out the Gearsmas festivities, The Coalition will be sharing even more holiday fun throughout December, starting with the UIR Gear Pack with specific dates and details coming next week. Finally, to get you into Gears on the big day, there may or may not be a special Easter Egg in the campaign, so players should stay sharp and get into the Gearsmas celebration while it lasts.
https://www.youtube.com/watch?v=NAgaLMsDFS8&t=0s
Source: Xbox Wire