Yes. During early development it was announced that there were 3 games planned. Since it seems to be a 10 year plan there will probably be more. When they announced it would be originally a trilogy they also announced that after the initial release it would be next gen only consoles. Somehow this was lost on people and rumors started to spread that the vanilla game would be updated for 10 years. Oh and shortly after vanilla destiny launched it was confirmed by Bungie that work had already begun on "Destiny 2". I have no links but I'm sure a quick search would reveal the info.