Obviously there is no cure for the common cold. Just like the Corona Virus.
The answear for Cancer for the last 60 years is chemotherapy. Again profit by the chemical/pharma companies. There have been some research into using white blood cells to multiply outside body, and inject a large amount back in to fight the cancer (using own immune system). But that has been out of the news for a couple of years, it is mentioned in a Netflix doc done on a book. Emperor of all Maladies.
Back to Covid. Its changing its own structure (mutating). The best I can see is a flu shot that contains dead Covid virus, so the body can recognize it, and fight it. That is supposed to happen in 2021.