Preheat the grill to medium-high heat.
Grill the corn for about 10-12 minutes, turning occasionally, until it is tender and slightly charred.
Let the grilled corn cool slightly, then cut the kernels off the cob into a large bowl.
Add diced avocados, chopped red onion, halved cherry tomatoes, and cilantro to the corn.
Squeeze lime juice over the mixture and season with salt and pepper.
Gently toss everything together until just combined, being careful not to mash the avocados.
Serve immediately or chill for 30 minutes to allow flavors to meld.