If weight loss is your goal, exercise is great. And you should exercise rregularly. But reducing food (calorie) intake is far more effective, especially in the short-term. Keep exercising if you are already (and congratulations!), but if you aren’t making the progress you want with weight loss, you may need to look closer at your diet.
On the other hand, regular exercise and physical activity is absolutely essential to long-term weight maintenance for most people. You may not be able to exercise your weight off, but maintaining a weight loss is extremely difficult without regular exercise. The habit of exercise will provide you huge benefits, and will likely extend your health span. Just don’t depend on it entirely for weight loss.