Looks like we are getting the return of the 2013 style Cybermen as well as the new who UNIT team comprising of Kate Stewart and Osgood for Capaldis first series finale.
Hopefully we will find out how that Zygon peace treaty worked out from the Day of the Doctor! Also is Osgood trying to make her way through all the Doctors outfits?!
Below is taken from doctorwhotv.co.uk:
UNIT are back along with Kate Stewart (Jemma Redgrave) and Osgood (Ingrid Oliver) who now seems to be wearing a bow tie! The recently announced Michelle Gomez is also on set as the mysterious Gatekeeper of the Nethersphere.
The monsters, or at least one of the monsters, will be the Cybermen (2013).