In the last movie of TNG's generation, "Nemesis", near the end in the Scimitar (Shinzon's ship)... spoilers ahead...
Earlier in the movie the team discovers B-4, a prototype android constructed by Doctor Noonian Soong. A little later Data wished to give his brother the opportunity to expand his capabilities, in much the same way that he himself had in years past. Towards that end, Data willingly copied all of his memories to B-4, hoping that the added experiences would help B-4 to expand beyond his original programming. However, soon afterward, B-4 had to be deactivated because of the danger he posed to the Enterprise crew, as a result of Shinzon's tampering.
At the end:
Some of Data's memories began to surface as Picard left the android in his ready room, B-4 beginning to sing the song that Data had sung at Riker and Troi's wedding shortly before B-4's discovery. His future was uncertain.
Does anyone know if Data was slowly resurfacing through B-4 and might be still alive?