While Gwent's faction challenges have been mired with problems before, it would appear that CDPR has managed to fix pretty much everything, just in time for the newest one! As such, you might be interested to hear that this month's faction challenge pits Monsters and Northern Realms players against each other in a battle to unlock new cosmetics as well as in-game currency and card kegs.
You will find the full list of rewards right below, but it is worth mentioning that playing with friends or in the Arena will not count towards your progress, for obvious reasons. Thankfully, CDPR has now added an in-game counter to the Notifications tab, so if you're ever confused about how many wins you still need in order to unlock a fancy new border, it's now going to be very easy to figure it out. As for the rewards, here's what you can get:
Additionally, the winning faction will get "guaranteed first 3 draft slots of Arena runs from Friday, March 23rd to Monday, March 26th". To be perfectly honest, I'm not exactly sure what this means. My best guess is that if, for example, Northern Realms wins the faction challenge, the first 3 picks in Arena will be exclusively Northern Realm cards. If that's the case, then I agree it's a neat idea, but why limit it to only three days?
Whatever the case may be, the whole faction challenge will last until 12 PM (noon) CET on March 22nd, so if you're looking to grab any of the new borders you might want to hop in as soon as possible. Good luck, and if you need a bit more information make sure to visit the official website.