If I do strength and cardio in the same workout, which one should I start first?
It depends on your goals. If your goal is to run a 5 km, start with the treadmill. If it is to get stronger and toned, then do a 5-10 minute warm up and do a more intense strength training. When you start lifting weights first, your form is better than if you do it after cardio.
Keep in mind that cardio burns more calories than strength training, so by doing it at the end, your body is still burning fat even after you are done.
What I usually do for my own workout and more often with my clients is a 30-minute (lower or higher impact cardio exercises), so I do a warm up (walking/jogging including weight free exercises, similar to what we are going to do), then I switch between a strength and a cardio exercise. I love high intensity intervals because you are done in no time and it burns a ton of calories.
Read more here: Cardio or Weights: Which Comes First? From Military.com