If you are speaking to the person:
* "Jim works with Kim and you." This is correct, as it is directly addressing the person.
If you are referring to someone else:
* "Jim works with Kim and him/her." You would use "him" or "her" depending on the gender of the person you're referring to.
Alternatively, you could use:
* "Jim works with Kim and them." This is grammatically correct, but it might be considered less formal.