They did F-150 (Atlas) and Edge concepts, but that was back in 2014?Almost all concepts today are derived from the finalized production design, especially those from Ford or Lincoln.
Ford no longer does concept cars but it's an important part of marketing at Lincoln. I'm not a big fan of them because they create idealized versions of a car which leads to disappointment, but it's still effective marketing.
Aviator concept seems likely for New York, or some sort of concept. We have 3 all-new vehicles arriving over the next 3 years with Aviator, MKC, and mystery vehicle #2 (probably a Small EV Utility). If they are going to space out these things, they need to do something in NY.
The Next-Gen MKZ is a mystery at this point, it is probably much farther out.
It's not like there's been much new to have a concept of - Nothing else has been redesigned since then.
Aviator will be in NY, and I'm thinking we'll see an MKC (name) concept at one of next year's shows, with production model debuting the year after.