What are the best things to do to boost immune system

i have 7 ways to boost your immune system they are

1. eat protein at every meal

2. try to eat at least 5 cups of fruits and veggies a day

3. take a 10 min walk a few times a day

4. get vitamin d levels checked

5. reduce stress levels

6. cook with olive oils and canola oils

7. limit your drinks