Corresponding SSU was released in May, if I'm not mistaken. It doesn't require reboot and really small one.
If you're not up-to-date with Windows updates you will get error “the update is not applicable....” while trying to install KB4345418 for Windows 2016.
This is because KB4345418 replaces KB4132216 which has KB4132216 (released in May) as a prerequisite.
Prerequisite: The servicing stack update (SSU) (KB4132216) must be installed before installing the latest cumulative update (LCU) (KB4338814). The LCU will not be reported as applicable until the SSU is installed.
https://support.microsoft.com/en-us/help/4338814/windows-10-update-kb4338814
Looks like the article for KB4345418 doesn’t mention that.