I was checking WWDC-2018 (Platforms State of the Union event for developers). Apple outlined a number of new protections that are coming to the Mac OS Mojave and iOS 12.
One of the points was notarization review of Mac OS application before distributing it, so that user may know it's safe from Malware etc.
Is it same for iOS enterprise apps? Will we have to get our iOS apps reviewed before distributing them to customers?
No, because you don't distribute enterprise apps to customers. You distribute them to employees.
Notarized macOS apps can be made available to the general public. Notarization gives consumers an assurance that the app they are installing has been reviewed by Apple and has not been tampered with, even though they are not getting it from the Mac App Store.
The terms of the enterprise program only allows distribution to employees of the particular enterprise.
Apple assumes that you are happy with the content and behaviour of the apps you have developed and that you have sufficient control over your signing keys and distribution method so rogue apps are not a problem.