Your immunity is definitely improved with your lifestyle. Make sure that you get enough sleep every day. A well-rested body has a strong immune system. Consume whole plant foods with antioxidants. Switch to healthy fats and avoid junk food as much as possible. Limit your consumption of added sugars and as much as possible, use natural sugar. Exercise every day. You should control your stress levels. Increase your friend circle as it has been observed that people with a vibrant friend circle have a better immunity. Drink lots of water because it washes the toxins away and keeps your body hydrated.