from the official site:

Our first Special Task Force mission is now ready for you and your friends to enjoy.
In "Infected," you'll travel to the Sibiran system to investigate Starbase 82, a Federation space station that has ceased communicating with Starfleet. As you arrive, you're in for a true nightmare scenario: The Borg have taken Starbase 82, and are in the process of assimilating the people aboard!
As you investigate the station, an acquaintance from your past is looking forward to greeting you in an epic encounter that will require skill, teamwork and maybe a little bit of luck to survive.

Quick "Infected" Facts
Klingon and Federation players both have access to this Special Task Force.
It is a daily repeatable mission.
Mark X gear drops in the mission.
Mission success provides Marks of Valor, which will be used in a special gear store coming in the 45-day update.
The Federation and Klingon Empire are now tentatively working together to fight the Borg and can be on the same Deepspace encounter maps against the Borg.