Hi Jan,
I understand that, the data and file name have to be imported to workspace when you select the file.
However 'cmRead' does not seem to be a valid MATLAB command.
I hope the 'uigetfile' function would help you get expected functionality for which the link is given below.
https://www.mathworks.com/help/matlab/ref/uigetfile.html?searchHighlight=uigetfile&s_tid=doc_srchtitle