Brian Horton, the Senior Art Director at Crystal Dynamics, is really excited that the next Tomb Raider has been announced so he can talk about it. Horton explained the direction of the sequel's story, saying that "The Tomb Raider sequel is the next chapter of [Lara’s] development… her life is changing. She can’t go back to the way she was."
So it looks like this will still be a prequel to the Lara we know from the older games, but I think that could be an interesting story. In Tomb Raider we saw what started to make her into the character we're familiar with, but the story really didn't get that far. I loved Tomb Raider, and this has gone on my list of my most anticipated games.
Tomb Raider Sequel is ‘Next chapter of Lara’s development’ [Electronic Theatre]