You may experience something wrong with your vim color scheme after you installed TMUX, something like:

Vim Tmux Screenshot

TMUX really wants the terminal set to screen, not xterm.
to fix this, simply add this line to your ~/.bashrc file:

export TERM="screen-256color"

to make sure you’re doing it properly, login to TMUX and type the command below:

echo $TERM

if terminal show you “screen-256color” then everything should be fine. you can start your vim now.