Posted at Nvidia Geforce Italy Facebook page, the teaser does not reveal any details, but since the company has already released their GTX 1080 Ti and Titan Xp, it is highly unlikely that it will be releasing a new GPU.
It is also possible that Nvidia wants to reign on AMD's Radeon RX 500 series refresh parade by giving a bit more promotion to its new GTX 1080 and GTX 1060 graphics cards, which comes with faster memory.
There are plenty of rumors floating around so it is anyone's guess. Some rumors suggest a possible new product in Nvidia Shield lineup, like a new gaming tablet or Android TV console or even a smart home device.
There is still plenty of April left and we will probably hear more about it after Easter.