Basically, coronavirus curve runs its course in leader’s absence, resulting in dead bodies! (9)

'dead bodies' is the definition.
(carcass is a kind of dead body)

'basically coronavirus curve runs' is the wordplay.
'basically' says to take the initial letters (the first letter could be its root or base).
'curve' becomes 'arc' (synonyms).
'runs' becomes 'asses' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letter of 'coronavirus' is 'c'.
'c'+'arc'+'asses'='CARCASSES'

'its course in leader's absence resulting in' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?