(adsbygoogle = window.adsbygoogle || []).push({}); For this week's Weekly Challenge, you are required to earn "200 Multikills in multiplayer Matchmaking this week." This challenge comes with a reward of 25,000 cR, which is fairly good. The tip for this week's Weekly Challenge is fairly basic, although with that said, there isn't much depth to this challenge anyway.
So, this week you're designated to obtain Multikills. These are most easily unlocked in the following playlist:

Grifball:
In Grifball, we have a virtually a one-hit kill system and the spawn system is hectic - there are only 4 spawns on each of the maps. If you run to their spawn, you can get some serious Multikills in Grifball.

Multi Team:
In Multi Team, we have several people that tend to bunch up together, particularly on maps that aren't big. This is ideal for Multikills.
Team SWAT:
Team SWAT is certainly another alternative to complete this challenge, with the fact that it's one shot to the enemy kill (to the head), Multikills can occur easily.
So that concludes this week's tip - play Grifball or Multi Team and you'll get it in time.