Difference between Facetious and Tongue-in-cheek

What is the difference between Facetious and Tongue-in-cheek?

Facetious as an adjective is treating serious issues with deliberately inappropriate humor; flippant. while Tongue-in-cheek as an adjective is not intended seriously; jocular or humorous

We hope you now know whether to use Facetious or Tongue-in-cheek in your sentence.