Yuugo: Koushounin

Both shows have negotiations, spies and action! O_o 

A Japanese man, very well educated and skilled in the art of rectifying issues between individual as well asfactions travels the worlds trouble spots solving mysteries and calming explosive situations. Another contemporary setting but the look and feel is a bit different. If you are looking for something more mature and thoughtful take a look at Yugo the Negotiator. 

Roger Smith and Yugo are negotiators who don't kill people and use weapons. Except that Big O is set in a fictional noir city while Yugo is set in Pakistan and Russia.