See the below links for command line switches / shortcuts by @lilles for Windows & Mac.
Open separate parts of eM Client directly for Mail, Calendar, Contacts, Tasks etc via switches / shortcuts Windows
https://forum.emclient.com/t/shortcut-to-open-em-calendar/55827/7
Open separate parts of eM Client directly for Mail, Calendar, Contacts, Tasks etc via switches / shortcuts Mac
https://forum.emclient.com/t/shortcut-to-open-em-calendar/55827/12