The Mates are the dance partners of the Huawei P series - the P9 leads with a Leica dual camera, now the Huawei Mate 9 follows with an improved version. Thanks to the next-generation chipset, that camera now records 4K 2160p video as well.
Source: http://www.gsmarena.com/huawei_mate_9_handson-review-1516.php