Earlier last year, Lenovo announced that it would phase out the Moto brand to introduce a new 'Moto by Lenovo' brand, with the aim to launch all its smartphones under the Lenovo umbrella. A year later, it recanted that strategy, and added that even its Zuk Mobile brand would be phased out soon. Now, noted analyst Pan Jiutang claims that Lenovo's Chinese sub-brand Zuk Mobile is shutting down in the next few weeks. The online-only brand will presumably be absorbed in the previously 'one-brand' strategy as well.
Weibo user named Old Cool posted that Lenovo would not be launching the Zuk Z3, to which the analyst replied that the entire Zuk vertical will be shut down in a few weeks. The online-only brand was launched by Lenovo to tackle the growing Internet-era brands like Xiaomi in 2015, and it has so far launched only five devices in the market. The first one being the Zuk Z1 and the last one was launched in December last year - Zuk Edge. If Jiutang's claims are true, then there may be no Zuk smartphones at all in the future, let alone the Zuk Z3.
If this is true, Zuk will reportedly shut down its operations in just 23 months of its existence, and will combine with Lenovo and Moto to form a new brand in the future. For now, Lenovo is pushing its Moto smartphones as is, and future phones will continue to use the Moto 'bat wing' logo. This could probably be because Lenovo would want to leverage from the legacy brand as much as it can.
None of this is certain for now, and there has been no official word from Motorola, so it's best not to jump to conclusions. Even if any of the above listed scenarios are true, the ZUI skin will presumably still stay, as Lenovo's Vice-President Alex Chen Yu recently confirmed that upcoming Moto smartphones will feature Zuk's ZUI skin.