Last year, there were many signs indicating that China’s Mario Kart 8 Deluxe online play is region locked.
Today, the official Mario Kart 8 Deluxe website for China has confirmed that that is the case – players with the Tencent version of Mario Kart 8 Deluxe could only play against others with the Tencent version, so there’s no way for them to compete with others outside China: