Pilot Hunter is a game mode in Titanfall. It plays very similarly to Attrition with the major difference being that only Pilot kills are tracked. The game lasts for 15 minutes and has a score limit of 50. This game mode has been removed from the PC version due to lack of demand.
Since this mode only counts Pilot kills, Pilots should be your main concern. However, AI controlled Grunts and Spectres are still present, just like in Attrition. Killing them still counts towards Titan Build time, so don't ignore them. With Pilots being your main concern, you should expect the target already on your back to be bigger as players who focus only on killing pilots comes after you. However, you can use their aggressiveness against them by employing different strategies, like baiting them into running into a cleverly planted Satchel Charge or Arc Mine.