Death certificates are made up of 4 parts:
1(a) Disease or condition that directly lead to death.
This could be pneumonia, acute kidney failure, multi-organ failure, pulmonary oedema, sepsis, etc.
1 (b) Other disease or condition, if any, leading to 1 (a).
This could be left-ventricular heart failure, chronic kidney disease, a cancer, a fracture with long-lie, a virus such as Corona virus, etc.
1 (c) Other disease or condition, if any, leading to 1 (b).
Something like diabetes may go here. Any condition that lead to another condition that caused death.
II) Other conditions CONTRIBUTING TO THE DEATH but not related to the disease or condition causing it.
Conditions such as previous surgery, chronic conditions such as dementia, Parkinson's, obesity, etc.
An example might be
1a) acute kidney failure
1b) Fractured hip with associated long-lie (e.g. fell over and didn't get help for 2 days).
1c) Osteoporosis
II) Dementia
So, a confused patient with dementia fell over and broke their hip, then because they weren't found for 36 hours, they went into kidney failure due to dehydration.
So Coronavirus may be listed on the certificate as a contributory factor or a primary factor.
It's splitting hairs a bit. Would they have died from CV19 if they hadn't had cancer? No. But would they have died at this time if they hadn't got CV19? No.