It's been more than a month since Assassin's Creed III release, and recently also premiered AC3 Tyranny of King Washington DLC, according to Gameinformer; Ubisoft Brazil managing director Bertrand Chaverot has revealed to a Portuguese tech site that the next entry of Assassin's Creed will be taking place in Brazil.
This could be quite possible, we could be for example going round Rio De Janeiro or Brasilia, especially that one of the Desmond story missions takes place in a Stadium in Brazil, and also the tree climbing mechanism can easily apply to the huge Amazon Rainforest. There is no quite sure timezone yet, but this would be a sequel with good potential for the future and what is yet to come in the AC Universe. Assassin's Creed have released a game yearly since Assassin's Creed II in 2009, followed by Brotherhood in 2010, Revelations in 2011 and AC3 this year. Only time will tell if this is a true claim, and we should find out sometime next year.