Of course it does Emmie but the vast majority of us had a winter (2019/2020), followed by a lockdown, followed by another winter and another lockdown. Virtually no one got enough exposure to the sun to get any meaningful amount of Vitamin D except for outdoor keyworkers...
I never put much stock in it myself until I started working for two Immunologists. Virtually all their patients, regardless of what conditions or symptoms they present with, are Vitamin D deplete. Practically all of them see a resolution of symptoms when their levels are replaced.
A lot of my chronic problems (IBS, insomnia, fatigue, low mood, etc.) are now gone since I started taking it.
I was told (by one of the aforementioned Immunologists) to take Vitamin D and calcium to repair the scarring in my lungs following my pneumonia and it seems to have done the trick according to my repeat CXR and follow-up with the Respiratory Physician.