Three Meat and Okra Gumbo

Name: Three Meat and Okra Gumbo
Ingredients: 1 lb boneless, skinless chicken (cut into bite-sized pieces); 1 lb shrimp (peeled and deveined); 1 lb smoked andouille sausage (sliced diagonally); 1 tsp Cajun seasoning (plus more to sprinkle on meats); 4 tbsp butter; 1/4 cup flour; 1 large onion (diced); 12 oz frozen sliced okra; 4 cloves garlic (minced); 3 bell peppers (red, yellow, and green, diced); 28 oz canned diced tomatoes (undrained); 48 oz box chicken or seafood broth; 1 tsp black pepper; 1/4-1/2 tsp cayenne pepper (or to taste)