is a combination of the 代名詞（だいめいし） (substitute noun) それ
, and the 副助詞（ふくじょし） (adverbial particle) でも
. It is often translated simply as ‘even so’, or ‘nevertheless’. Literally, it is a bit closer to ‘even with that’.
is usually used between an (A) and a (B) phrase, to show that there is more information (usually surprising) to be considered.
It's going to rain today, even with that, are you still going fishing?
I don't like getting punched or kicked, even so, I like karate so it is hard to quit.
This grammar point primarily expresses that ‘even with’ what has been said previously, it is not all there is to think about.