Huawei has revealed that it will be launching the flagship Mate 30 series "in September or October".
The info came from Huawei product manager Bruce Lee at a P30 event in Malaysia. The Mate 20 series was launched on 16 October last year, so expect the Mate 30 to be with us around the same time this year.
While the P30 is powered by the Kirin 980 platform from the Mate 20 Pro, the Mate 30 lineup will have an enhanced chipset - maybe Kirin 990 - which Huawei will probably talk about in the late Summer or beginning of September. We attended a Kirin 980 briefing at IFA 2018, for example.
Expect four or even five cameras to be inside the Mate 30 Pro which will surely have the enhanced 10x hybrid zoom from the P30 Pro. Given the launch date, it'll probably be running EMUI 10, the upcoming version of Huawei's Android skin. Presumably, that will be based on Android Q.
While 5G wasn't mentioned for the recently-announced P30 and P30 Pro, the Mate X foldable will be a 5G handset. We'd also expect the Mate 30 series to be 5G compatible, not least because there will be 5G networks live by the time of its launch.