On some of the more recent versions of Mac OS, installation of programs from outside the App Store is made more difficult. One of the following two methods should resolve any issues.
Method One - Change Gatekeeper Settings
1. Open the System Preferences. This can be done by either clicking on the System Preferences icon in the Dock or by going to Apple Menu > System Preferences.
2. Open the Security & Privacy pane by clicking Security & Privacy.
3. Make sure that the General tab is selected. Click the icon labeled Click the lock to make changes.
4. Enter your username and password into the prompt that appears and click Unlock.
5. Under the section labeled Allow applications downloaded from:, select Anywhere. On the prompt that appears, click Allow From Anywhere.
6. Exit System Preferences by clicking the red button in the upper left of the window. You should now be able to install applications downloaded from the internet.
Source: https://kb.wisc.edu/helpdesk/page.php?id=25443
Method Two - Drag Install File Into Terminal Window
1. Navigate to the downloaded Install File, right click, select "Show Package Contents".
2. Navigate to /adobe/Install.app/Contents/MacOS/ and you should see an Install file.
3. Go to Finder, search for Terminal, and open up a Terminal.
4. Drag the install file from step 2 into the Terminal window, press Enter, and installation should start normally.
Source: https://forums.adobe.com/thread/2223420
Source: https://helpx.adobe.com/ru/creative-cloud/kb/install-creative-suite-mac-os-sierra.html