http://www.techradar.com/news/call-of-duty-2018-release-date-news-and-rumors

Call of Duty is one of those franchises that you can count on. Like FIFA, it doesn’t miss its yearly slot on the release calendar and, to be frank, we like that kind of stability in our gaming lives. 

Even though it hasn’t been confirmed by Activision just yet, we feel quite comfortable in saying that there’ll be a Call of Duty game released in 2018. Last year's Call of Duty WW2 was largely well-received and there was an uptick in the sales figures, so there isn’t really any reason to cut the series off here.