macOS often blocks apps from "unidentified developers." You may need to go to System Settings > Privacy & Security to allow the installer to run.
macOS 10.11 (El Capitan), 10.12 (Sierra), or 10.13 (High Sierra). adobe-illustrator-cc-2018-v22-1-0-312-macosx-2-2gb-2022
If prompted to sign in or buy, select the "Trial" or "Install" option. macOS often blocks apps from "unidentified developers
This is common if you have remnants of other Adobe versions. Download the Adobe Creative Cloud Cleaner Tool from the official Adobe site to wipe old files before trying again. adobe-illustrator-cc-2018-v22-1-0-312-macosx-2-2gb-2022