Cook the tortellini according to package instructions until al dente, then drain and rinse under cold water.
In a large bowl, combine the cooked tortellini, cherry tomatoes, cucumber, bell pepper, red onion, and olives.
Add the crumbled feta cheese and chopped basil to the bowl with the tortellini and vegetables.
In a separate small bowl, whisk together the olive oil, red wine vinegar, Italian seasoning, salt, and pepper until well combined.
Pour the dressing over the tortellini salad and gently toss until everything is well coated.
Taste and adjust seasoning if necessary, adding more salt, pepper, or vinegar as desired.
Cover the salad and refrigerate for at least 30 minutes before serving to let the flavors meld.
Serve chilled or at room temperature, garnished with additional basil if desired.