head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Competitive PvP
Blockbuster 2009 sequel famous for killstreak chains and frantic multiplayer.

Execution · Pure Mechanics
An arena shooter built on precision aim and power-weapon map control.
Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP); Halo Infinite leans Execution (Pure Mechanics).
Halo Infinite leans a little harder on execution, though the gap is small.
Call of Duty: Modern Warfare 2
Fast time-to-kill rewards raw aim and reflex
Halo Infinite
Precision aim and strafe duels dominate.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2
Outguessing human rotations and flanks
Halo Infinite
Adaptive opponents around power weapon timings.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
Halo Infinite
Spawn flips and weapon drops add noise.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2
Killstreak economy, loadout and map knowledge
Halo Infinite
Map control, weapon timers, and team callouts.
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.