Fat loss can’t occur by cardio alone. Cardio combined with eating within your goals can enhance fat loss in 2 ways though by burning calories and speeding up your BMR (using different HIIT forms)
If you don’t do cardio correctly then it won’t help. For example if you’re trying to lose weight and have eaten 600 more calories than your body has burn for the day. So you go jogging for 30 minutes later that day which burns around 300 calories with maybe another 100 burned from the “after burn” effect. You would still be 200 over your expenditure and that means no reduction in your fat stores for the day, and you may actually gain weight.
Eating to your goals and working out leads to the results you want!