You won't be able to find Pantone Color books anymore if you are using the latest Adobe Illustrator version, v28.0 onwards. The good news is, there is a way to do that. In this guide
4 Color Process Printing and Spot Color Printing - What's the Difference?
Where Are the Pantone Colors in Adobe Illustrator?
4 Easy Ways to Find And Install Pantone Color In Illustrator
How to Find & Use Pantone Colors in Adobe Illustrator
How To Vectorize An Image In Illustrator: 3 Easy Ways
Restoring Pantone Colors in New Illustrator Versions
Where Are the Pantone Colors in Adobe Illustrator?
How to find a Pantone Color in Illustrator? - Graphic Design Stack Exchange
Why Is Illustrator Bounding Box Not Showing [8 Easy Fixes]
Adobe and Pantone Color Books: Quick & Easy Way to Save as Swatches and/or Copy .ACB Files Over to New Version
2 Easy Ways To Superscript In Illustrator You Should Know
How to Find Pantone Colors in Adobe Illustrator & Photoshop