There is a really nice utility for Mac called PDF to Keynote that is able to export presentations in PDF format (prepared for example in LateX) to Keynote's KEY presentation format.
Convert Adobe Portable document format to iWork Keynote '09 presentation.
We found 2 software records in the database related to .pdf to .key file format conversion.
Apple macOS / Mac OS X software - convert pdf to key on OS X
A simple PDF to Keynote converter
Convert from pdf file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned pdf to key. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A dedicated document converter