Cue lists themselves do not contain tempo info. Each cue only contains an absolute time position. The tempo slider on Show Control simply adjusts a global tempo for the entire project.
When playing, cue times are scaled to match the global tempo. So, if tempo=200%, a 10-second long cue will play out in 5 seconds, and a line set to start at 00:30 will start at 00:15.
When editing a cue list, the waveform/cues display at the bottom of the window reflect the current master tempo. So, if you created a cue list with the master tempo of 170%, you would need to play back at 170% for the cues to line up with your audio track correctly.