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 · Competitive PvP
Shot-timing execution against adapting human defense, on top of build and playbook math.
Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP); NBA 2K17 leans Execution (Competitive PvP).
Call of Duty: Modern Warfare 2 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
NBA 2K17
Shot meter timing and dribble execution decide possessions
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
NBA 2K17
Online opponents adapt defensive schemes and bait plays
Call of Duty: Modern Warfare 2 leans a little harder on variance, though the gap is small.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
NBA 2K17
Shot RNG wraps the timing meter
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
NBA 2K17
Build math, playbooks and matchup hunting underpin wins
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.