head to head
Neither is simply harder - they are hard in different places. Call of Duty: Black Ops demands more variance; The King of Fighters '98 demands more reads.

Execution · Competitive PvP
Cold War-era shooter pairing twitch multiplayer with the cult Zombies mode.

Execution · Competitive PvP
The classic 'dream match' team fighter widely held as KOF's most balanced competitive entry.
Call of Duty: Black Ops leans Execution (Competitive PvP); The King of Fighters '98 leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops
Gunfights hinge on aim and reaction speed
The King of Fighters '98
Strict inputs, short hops, tight punishes
The King of Fighters '98 leans clearly harder on reads.
Call of Duty: Black Ops
Reading human opponents' positioning and timing
The King of Fighters '98
Human opponents constantly adapt and condition you
Call of Duty: Black Ops leans clearly harder on variance.
Call of Duty: Black Ops
Spawns, care packages, zombies RNG
The King of Fighters '98
Near-fully visible game state
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops
Class builds, map control, zombies routing
The King of Fighters '98
Team order and matchup theory reward study
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.