A couple of rumours which have indicated that a new expansion pack might be coming this year.The rumour comes after someone found this in the steam database.
As you can see there have been added to new items to the list which are One World Content and One World EXE.
So this presumably means that the new Expansion will be called One World. So what could it be about a survival game where you only have a limited amount of recourses. Who knows
Anyway this rumour has started and its starting to put energy in this civ community which I like.