A PCB (printed circuit board) refers to any circuit board, including a PCM and a BMS.
A PCM (protection circuit module) is a simple PCB that grants protection capability to a battery pack. Usually overcharge, over discharge, overvoltage, undervoltage, and short-circuit. Including a thermistor will also enable over-temperature. PCMs are used for most packs.
A BMS (battery management system) is more sophisticated than a PCM, and only for larger packs (usually above 10S). These include balancing, and a communication protocol so it can send data to a computer. BMSs are used for electric vehicles, and other large packs. Adding a communication protocol is complicated, and will increase the time to design the pack and manufacturer it.
Some packs are bare (unprotected) and without any PCB. For example, sometimes aerial vehicles save on weight and to allow the craft to go into undervoltage conditions so they can land safely in an emergency.