Preheat oven to 375°F (190°C) as a backup reheating option.
Peel husks from corn and cut into 6-ounce rounds per ear.
Cut the onion into 1/4-inch slices and mince the garlic.
Slice the bell pepper into thin strips.
Heat 3 tablespoons of butter or olive oil in a skillet over medium heat until it starts to sizzle.
Add onion and bell pepper to the skillet and sauté for 5–7 minutes, stirring occasionally, until tender.
Add minced garlic, corn, ½ tablespoon Cajun seasoning, ½ teaspoon salt, and ¼ teaspoon black pepper to the skillet.
Cook for 3–4 minutes until the corn slightly caramelizes and softens.
Meanwhile, brush both sides of tilapia fillets with 1 tablespoon of melted butter or olive oil.
Season the fillets with 1 teaspoon of kosher salt and the remaining ½ tablespoon Cajun seasoning.
Grill the tilapia on medium heat for 3–4 minutes per side or until fully cooked and flaky.
Serve the grilled tilapia with the Cajun skillet sides for a complete meal.