Which graphic tablet are you using?
Did you set it up according to the manufacturer's description?
OS: Windows 10
Tablet: Wacom Intuos
I installed the latest driver and pen pressure works fine except in Illustrator. Maybe reinstalling the software will fix it?
Please contact Wacom on how to properly install the driver.
I know from experience that it is not straightforward these days. You have to uninstall in certain ways and then also reinstall. And then again you might need to set this up in your system. I don't know how paranoid Windows is, but on Mac OS it's actually a pain in the rear.
Sorry about the delay. I am hopeful that the issue was fixed. If not, please try the suggestions shared on this page ( https://helpx.adobe.com/in/illustrator/kb/illustrator-cc-crash-wacom-drivers.html ) and let us know how it goes.
Feel free to let us know if you still need assistance. We'd be happy to help.