Although a combination of the substitute noun 何（なに） and the imperative form of する, しろ, 何（なに）しろ
is often considered to be a singular adverb that carries the meaning of ‘no wonder’, or ‘after all’. A more literal translation would be something like ‘whatever the case, (A)’, and just expresses that in any circumstance, only one conclusion can accurately be drawn in regard to (A).
will frequently appear at the beginning of a sentence, or at the start of the second clause.
After all, he is new, so please cut him some slack.
It's no wonder he can do it. After all, he is a professional.
will regularly be seen partnered with statements including words like から or ので, in order to emphasize an explanation or reason as to why (A) is the way it is.
After all, it was hotter than usual today, so I'm exhausted.
After all, this product is too inconvenient and will not sell no matter how low the price goes.