The DWM1001 fits a DW1000 UWB transceiver as well as a nrf52832 with BLE.
The DW1000 is an UWB radio used to provide very accurate timestamps. It enables measurement of accurate distances. In order to perform correctly, the DW1000 must be coupled with a micro-controller (mcu) that will basically control its behavior by sending instructions (such as receive/transmit).
The nrf52832 is the mcu used to program/control the DW1000 within the DWM1001.
It offers a BLE interface allowing connection to other BLE devices. This is very useful for low power data transfer for example, but it does not enable accurate distance calculation as the DW1000 does.
Note that we could have used a different micro-controller (there are a whole variety of them on the market), but the DW1000 is the main solution on the market to perform such accurate timestamping with UWB.