Ubisoft has hinted that there will be a fourth installment into the Call of Juarez franchise by sending out a survey to players of Call of Juarez: The Cartel that synced the game with their UPlay accounts.
Very few details were given in the survey, but one of the questions asked what kind of set-piece they'd like to see in a game. Two of the options were: preventing a bank robber and preventing outlaws from pillaging a gold mine.
While the Call of Juarez franchise has never been a massive critical success, the first two games garnered a following due to their depiction of colonial America. The third game became much more relevant as it was set in modern day Los Angeles.
Source: The Gaming Liberty