Preheat the grill to medium-high heat. Grill the corn for about 10 minutes, turning occasionally until charred. Remove from heat and let cool before cutting the kernels off the cob.

In a large mixing bowl, combine the grilled corn kernels, cherry tomatoes, red onion, cilantro, and avocado.

In a separate bowl, whisk together the mayonnaise, sour cream, lime juice, chili powder, salt, and black pepper until smooth.

Pour the dressing over the salad mixture and toss gently to combine. Top with crumbled cotija cheese and lime zest before serving.