Have you met the case that Emacs in iterm2 on Mac does not recognize
M-S-RET (Meta(Option)+Shift+ Return key)? I guess it's related to the modifier key conversions in terminals.
M-S-RET is used in org-mode
describe-key in Emacs and got
M-[1 3; 4
M stands for meta, 13 is the ASCII code of
return, 4 is the CSI u code for
Shift+Alt see http://www.leonerd.org.uk/hacks/fixterms/