Sacrifice for me has to involve million dead (8)
I believe the answer is:
immolate
'sacrifice' is the definition.
(I know that immolate is a more specific form of the action sacrifice)
'me has to involve million dead' is the wordplay.
'me has' becomes 'imo' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to involve' means one lot of letters goes inside another (inserted letters get involved).
'million' becomes 'm' (abbreviation).
'dead' becomes 'late' (similar in meaning).
'imo' going around 'm' is 'immo'.
'immo'+'late'='IMMOLATE'
'for' is the link.
Can you help me to learn more?
(Other definitions for immolate that I've seen before include "Offer as sacrifice (usually by burning)" , "Sacrifice, kill or destroy" , "Destroy; burn" , "Limo team involved in sacrifice" .)