How to deal with a feature that has lot of categorical values?
one idea is to craft some features of this feature - when you classify cars you don't have data like strings "Ferrari 991 year 2014 red" "BMW z4 year 1999 2.0L blue" but you would like to have columns like "Manufacturer", "Type(SUV/Cabrio...)", "Year", "Engine" etc.

you could transform it or just discard