TCL is one of a handful of companies to bring foldable technology prototypes to this year's MWC. Interestingly, this company's demo models include form-factors besides phone/tablets. However, their presentation was a little low on detail.
https://www.notebookcheck.net/TLC-s-folding-prototypes-make-it-to-MWC.410788.0.html
So TCL is the first one to show (a prototype) of a foldable actual phone, rather than a folding tablet.