Season the chicken and sausage with Cajun seasoning.
Heat vegetable oil in a large pot over medium heat. Sear the chicken and sausage until browned. Remove and set aside.
In the same pot, make a roux by combining the vegetable oil and flour. Stir constantly over medium heat until the roux turns a dark brown color.
Add the bell pepper, celery, onion, and garlic to the roux. Cook until vegetables are soft.
Gradually stir in the chicken broth, bringing the mixture to a simmer.
Add the okra, black pepper, hot sauce, and gumbo file powder. Stir to combine.
Return the chicken and sausage to the pot. Simmer for 1 hour, stirring occasionally.
Season with salt to taste and serve hot over white rice.