Gumbo Filé is a thickening agent in creole cooking. You should keep some in your stash of staples. It's similar to how okra thickens stews; but the ground leaves of the sassafras tree adds an extra dimension of earthiness.
Here's Hank Williams and Jumbalaya . . .
Some Louisiana Hot Saucy . . .
The definitive recipe from New Orleans Cajun Justin Wilson . . .