Similar to vim-tmux-navigator but for Emacs & Tmux.

tmux-emacs-windmove.el

(defun wpcarro/tmux-emacs-windmove (dir)
  "Move windows in a Tmux-friendly way."
  (let* ((dir->opts '((left . ("-L" . windmove-left))
                      (right . ("-R" . windmove-right))
                      (above . ("-U" . windmove-up))
                      (below . ("-D" . windmove-down))))
         (opts (alist-get dir dir->opts))
         (tmux-opt (car opts))
         (emacs-fn (cdr opts)))
    (if (window-in-direction dir)
        (funcall emacs-fn)
      (shell-command (format "tmux select-pane %s" tmux-opt)))))

See vim-tmux-navigator for an example of the precedent.