I'm using tmux for many years now and I would not go back. But one feature was always lacking: italics.
Vim shows HTML attributes in italic for example, but in tmux I could not use this feature. There are many guides available on the web, but all require some kind of fiddling with the terminfo db or whatnot.
But, since tmux 2.1 there is a setting to enable correct italic handling in tmux
itself, see this wiki entry
If you want to have a consistent 256-color support (you probably want to) you
have to use
tmux-256color. So, add this to your
set -g default-terminal "tmux-256color"
Now I only had to change the font settings in my terminal,
I'm using Fira Code (I really like the
-->), but apparently there are no italic glyphs. Therefore I had to
configure kitty to use a different font for italics. For this, only add the
italic_font Source Code Pro bold_italic_font Source Code Pro
Source Code Pro to any other font you would like to use.
And thats it! I finally have italics in my setup :D