Halo 3's release on PC has helped The Master Chief Collection's player population on Steam surge.

Steam's own publicly available data shows that The Master Chief Collection reached a peak concurrent player base of 54,761 people on launch day, July 14. With numbers that big, MCC moved inside of the Top 10 list for the most-played games on Steam's entire platform.

Halo 3 and MCC are also available to buy on PC directly from Microsoft's Store, while Xbox Game Pass members on PC can get the games, too. As such, the total player count for Halo 3 and MCC overall is surely much higher.