Once the installation is complete, you'll need to activate Adobe Illustrator CC 2020 using your Adobe ID:
sudo spctl --master-disable sudo defaults write /var/db/SystemPolicy-prefs.plist enabled -string no
Open Terminal and type:
Ensure you have the Illustrator CC 2020 DMG file. If you are using a pre-activated or "exclusive" package, it typically comes as a Disk Image (.dmg) file.