This is a vector imaging format used in the CorelDRAW editor. It has a template that can be applied for other designs, including styles, grid parameters, page layout and other parameters. The CDT template allows for the creation of several images in one style without changing the settings in manual mode.
PSD is a file format that is created with Adobe Photoshop. This adobe proprietary file can contain layers, vector images, raster images, text etc. It also supports Gray, CMYK, and RGB etc color coding format. It can contain large amount of data in layers.