Likely use of aimbot and wallhack as well as possible spectator observation hack.

Player was observed for 4 minutes before abruptly leaving.

This video is fairly short, so I suggest simply watching the whole thing. Main points are very high rate of headshots, snapping to targets, and several instances that appear to suggest the use of wallhack. Watching from 2:00 to 2:15 shows what looks like a toggle lock and instant headshot for example.

In addition, his stats profile suggests a high HSKR as well.

https://bf4db.com/player/1133164686