The T-800 from the second film, at its own request, is then also destroyed to eliminate any future technology that could be used to create Skynet through reverse engineering. Despite this, at the beginning of the television series, a T-888 using the name "Cromartie" is sent back to 1999 to kill John.
The destruction of the T-800 in the second film was intended to prevent future technology from being used to create Skynet, and this action is mirrored in the television series where a T-888 named "Cromartie" is sent back to 1999 to kill John.