in any case vs besides

in any case and besides both are adverbs.

Word	Noun	Adjective	Verb	Adverb
in any case	No	No	No	Yes
besides	No	No	No	Yes

As adverbs, in any case and besides are synonyms defined as:

in any case (adverb)	besides (adverb)
used to indicate that a statement explains or supports a previous statement	making an additional point; anyway
making an additional point; anyway	in addition