Rumor: Developers started testing Tuscan
Dataminer reports on Valve's internal tests.
The CS: GO map pool hasn't been updated for a long time, and the latest rumors hint that a new map could appear as early as next season.
Dataminer Gabe Follower, on his Twitter, reported that the developers were testing de_prime and de_tuscan about a week ago. This may indicate the adding of these maps to the game. However, this does not guarantee their inclusion in the competitive map pool.