The well-known tech tipster IceUniverse claims to have attended a Vivo event in which this OEM outlined plans to use Samsung's newest SoC in a phone. This chipset, the Exynos 980, is thought to be best suited to mid-range phones - albeit ones with 5G. Vivo apparently plans to release just such a device before the end of 2019.
https://www.notebookcheck.net/Vivo-reportedly-announces-partnership-with-Samsung-to-make-a-5G-phone-with-the-Exynos-980.434446.0.html