Gumbo typically has one of the three thickeners - being okra, gumbo filé, or roux. Although some gumbos might have more than one of those.

It's also worth nothing that there are two cuisines in southern Louisiana of note: Cajun, and Creole. Although all of these topics are very complex, I would simplify those two to say that Cajun tends to be country and Creole tends to be city.

A Cajun gumbo is more typically a dark roux, trinity (diced onion, bell pepper, celery), usually sausage, andouille being most popular, either chicken or seafood but sometimes both, and various herbs and spices.

A Creole gumbo tends to add okra, might skip the roux, often adds some lemon and basil, and often diced tomato. My family's recipe didn't have roux and used kielbasa and chicken breast for the proteins. My version includes roux (retaining the okra) and uses kielbasa and chicken thighs.

Gumbo should be served over rice.

I'm trying to give a bit more info while steering clear of arguments. Everybody has their own gumbo recipes, and I will absolutely eat the fuck out of any of them at least once, and probably many times :)

So again, adding on to the comment to which I'm replying, not disagreeing! :)