Boil pasta according to package directions until tender.
Drain pasta and rinse with cold water completely.
Cut cherry tomatoes in half using sharp knife.
Dice red onion into small, uniform pieces carefully.
Cube fresh mozzarella into bite-sized pieces evenly.
Slice black olives into thin, round pieces.
Tear fresh basil leaves into smaller pieces gently.
Whisk olive oil with balsamic vinegar together.
Add Italian seasoning, salt, and pepper slowly.
Combine pasta with all vegetables in bowl.
Pour dressing over pasta mixture and toss.
Refrigerate for 30 minutes before serving chilled.