The inaugural CONCACAF Nations League will kick off in September 2019, but 2019-20 CONCACAF Nations League Qualifying is in full swing. The league will include every member of CONCACAF (except Guatemala - suspended by FIFA and barred from entering teams in international competitions when the schedule for Nations League qualifying was being finalized), so it is not so much a qualifying tournament that is being held as a giant sorting exercise.
Ultimately, CNL will see 40 teams divided into three tiers, each comprising its own “league” (multiple small groups, in point of fact), with promotion and relegation between them and a top tier that will deliver a Nations League champion in 2020.