Call of Duty uses an automated system to decide which players are placed together in online matches. The system considers factors like connection speed, how quickly a match can be found, and player skill — though Activision says skill is not the most important factor. In January 2024, Activision published its first-ever public explanation of how this system works.

Activision's matchmaking system prioritizes low-latency connections (ping) first, then time-to-match and playlist diversity, with skill considered as a secondary factor. Skill is calculated from kills, deaths, wins, and losses as a fluid measurement that shifts over time. Activision published an official white paper in 2024 revealing A/B test results showing that removing skill consideration from the matching algorithm reduced player retention — particularly for lower-skilled players who faced much stronger opponents. The system uses data-driven algorithmic optimization. Activision's broader research division has also published on machine learning approaches to player skill rating, though the company has not explicitly confirmed the live matchmaking system uses machine learning models rather than rules-based algorithms. The practice has been a long-running source of controversy in the Call of Duty community, with players alleging the system is manipulated to encourage in-game purchases — a claim Activision explicitly denied in its 2024 disclosure.