The Chicago Manual of Style if I am correct is a manual which details ways in writing/describing things, such as a booklet for a lawnmower that tells you how to assemble it.
The Chicago Manual of Style is more comprehensive than that. It has parts relevant to technical writing, parts relevant to academic work (it is a strong standard for citations, for example). A lot of journalism is written following the CMoS, and it also covers general grammar and style. So, noting the CMoS does not instantly imply technical writing.