Developers often use tmux panes and Vim windows to complement each other. You can have Vim open in different tmux panes as a way to isolate Vim instances from each other (and therefore group buffers). Normally, I have a few tmux panes open with Vim in one of them (with its own splits as needed), and shell running in the rest. Everyone treats their panes and windows differently, and you may want to experiment.

tmux and Vim use different key bindings to navigate through windows (or, in tmux terminology, panes). This is rather confusing, and there are solutions in place to fix it! The easiest is to use the vim-tmux-navigator plugin, which is available from https://github.com/christoomey/vim-tmux-navigator. vim-tmux-navigator adds support for consistent navigation between Vim windows and tmux panes using the Ctrl + h, Ctrl + j, Ctrl + k, and Ctrl + l keys.

Once you have the plugin installed, you'll have to add the following bindings to your ~/.tmux.conf file (this snippet is available from https://github.com/christoomey/vim-tmux-navigator):

# Smart pane switching with awareness of Vim splits.
# See: https://github.com/christoomey/vim-tmux-navigator
is_vim="ps -o state= -o comm= -t '#{pane_tty}' 
 | grep -iqE '^[^TXZ ]+ +(\S+\/)?g?(view|n?vim?x?)(diff)?$'"
bind-key -n C-h if-shell "$is_vim" "send-keys C-h" "select-pane -L"
bind-key -n C-j if-shell "$is_vim" "send-keys C-j" "select-pane -D"
bind-key -n C-k if-shell "$is_vim" "send-keys C-k" "select-pane -U"
bind-key -n C-l if-shell "$is_vim" "send-keys C-l" "select-pane -R"
bind-key -T copy-mode-vi C-h select-pane -L
bind-key -T copy-mode-vi C-j select-pane -D
bind-key -T copy-mode-vi C-k select-pane -U
bind-key -T copy-mode-vi C-l select-pane -R