Mass Effect 3 was the final episode of Commander Shepard's story but not the series, Kingdom Hearts III game director Tetsuya Nomura stated that this was the last episode of the trilogy, but it won't be the last game in the series.
According to Nomura, "As a core game, this is finally the third, and 10 years have passed. I couldn't call this a trilogy. There have been so many spinoffs. In Kingdom Hearts 3, the battles that the characters have been fighting for the past 10 years will come to a conclusion. That is the plan. But the series will continue. Only the particular enemy they have been fighting the past 10 years will come to an end."
Kingdom Hearts III will be released for PlayStation 4 and Xbox One. No release date has been announced.