CCM, located in Microsoft Windows' System32 folder, stands for Change and Configuration Management. It's a folder created to store temporary files for client installations as a part of the Systems Management Server (SMS) of Microsoft, which is responsible for deploying system-wide installations and updates.
SMS was Microsoft's enterprise management software that tracks hardware and software inventories, deploys software applications and updates and manages any software changes in a network environment. By 2007, this has become System Center Configuration Manager, which essentially performs the same tasks as SMS.
SMS or SCCM centralises the process of software installation into one management application. When a new software or update needs to be deployed, it creates the CCM folder in all computers until the installation or update finishes. The CCM folder contains the Advance Client Installer (ccmsetup.exe), which is responsible for initiating the installations in the computer.
The CCM folder is important at the time of the installation because it stores all the installation files locally in the computer. Instead of the computer maintaining a constant connection to the server, the installation runs locally in the computer, which saves bandwidth.