There are a few questions already posted about when and if Sombra can be seen with her camouflage active but so far this hasn't been brought up. As of right now there are only these 2 ultimates that directly lock-on to an enemy, but do they still target a Sombra that can't be seen?
Unless she is revealed by something else (being too close, sonic arrows or Infrared Sight) you should be untargettable.
On the other hand, you have to still be careful while being Sombra as damage will reveal you. Getting shot by 76 while he's targetting someone else is still a possibility. After that, you'll be targettable.