In a large mixing bowl, combine the halved cherry tomatoes and diced cucumber.

In a separate bowl, mix together the Greek yogurt, mayonnaise, olive oil, lemon juice, garlic powder, salt, and pepper until smooth.

Pour the creamy dressing over the tomatoes and cucumber, and gently toss to coat all the vegetables evenly.

Let the salad sit for 5 minutes to allow the flavors to meld.

Serve chilled, garnished with fresh basil leaves.