Weight training 😀 When you do weight training with things like compound movements your body not only burns calories while you’re training. But your body will still burn cals after you have finished as your body recovers it’s called an “afterburn effect” where as when you stop doing cardio so does the calorie burning
The real answer: anything you can reliably do consistently, because if you aren’t consistent then nothing will work. However, for long term weight loss you will want to do some weight training. It builds muscle which burns more calories at rest (it’s not a lot but it helps) and also allows you to do more aerobic activities as you get leaner. Cardio is still important though — you want to alternate days or do your cardio after the weight training.