Skynet's actions throughout the timeline causes a grandfather paradox, effectively changing all of history of the events leading to the future war, succeeding Skynet's goal in eliminating the Resistance established by Connor. However, it is heavily implied throughout the film that after the timeline's alteration, the party who saved Sarah has taken over the Resistance's place, having  their own time machine, and acts in anonymity to thwart Skynet's schemes and to prevent it from locating them.
Skynet's actions throughout the timeline cause a grandfather paradox, altering all of history leading up to the future war. This change enables Skynet to achieve its goal of eliminating the Resistance established by Connor. However, it is strongly suggested that after the timeline's alteration, the party who saved Sarah has taken over the Resistance's place, possessing their own time machine and operating in secret to thwart Skynet's plans and prevent it from locating them.