In games, it is very common for rich people to hire mercenaries to perform difficult tasks - trained gunmen who can kill any named person in a matter of hours.
Games about assassins and mercenaries are not only about our times. A great example is the Assassin's Creed series, which is about a medieval clan of assassins.
This list contains all the games that give gamers the opportunity to feel like they are in the role of a secretive killer or a mercenary who performs especially dangerous tasks to eliminate well-protected and dangerous individuals.