Since Vivo is already receiving both Exynos 980 and Exynos 880 chipsets from Samsung, it would not be surprising to see Xiaomi and Oppo joining them in the coming months. However, it seems that these two companies will only get budget chipsets from the tech giant headquartered in South Korea.
https://www.notebookcheck.net/Xiaomi-and-Oppo-to-join-Vivo-in-using-Exynos-chipsets-starting-next-year.501722.0.html