Even if you ignore the legal and security issues, Adobe Illustrator CS5 is a piece of software from 2010 that is no longer compatible with modern Mac operating systems.
Adobe now offers a web-based version of Illustrator for subscribers, which acts like a "portable" version because it runs in your browser without a full desktop install. Recommendation:
Adobe Illustrator CS5 Portable for Mac: A Comprehensive Guide to Free Download and Use Adobe Illustrator Cs5 Portable Free Download Mac
I can recommend a that matches your exact setup. Share public link
If you are looking for legitimate ways to access Adobe Illustrator, consider these alternatives: Even if you ignore the legal and security
Even if you find an unmodified version of Illustrator CS5, running it on modern Apple hardware presents massive technical hurdles.
Instead of risking your computer with a portable download, consider these legal, stable alternatives: Share public link If you are looking for
As noted in Adobe Community Forums , users have reported frequent crashes on save and quit even on older versions like macOS Sierra.