CWDM (Cold plus Warm Dark Matter) is defined as a Dark Matter which is a mixture of Cold Dark Matter and Warm Dark Matter. The main difference of CWDM and Warm Dark Matter is the behavior of the Dark Matter transfer function at small co-moving scales - while the Warm Dark Matter transfer function decreases exponentially (due to the finiteness of free-streaming length), CWDM transfer function fades much slower, reaching a plateau at large co-moving wave-numbers (see e.g. [1]).