After all the buzz Samsung's upcoming Galaxy F foldable smartphone has generated, rival OEMs are taking notice of the new form factor. One of these rivals, Oppo, recently filed a foldable smartphone design with the Chinese patent office SIPO. While a patent doesn't necessarily mean that a device is coming, it does show that Oppo is considering the idea of a foldable smartphone.
https://www.notebookcheck.net/Oppo-may-be-developing-its-own-foldable-smartphone.364316.0.html