In case is used when you do something just to make sure no matter whether a condition is met. With if the condition is a prerequisite/ I will get there by car just in case it rains. (It might rain and might not.
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doanbichngoc
I do A in case B happens => I do A because B might/ or might not happen => A just happens because you choose it to happen. (B can happen otherwise you will not write it, will you? It just sounds redundantg to me. You can substitute it for this : I do A. (without "in case". "In case" adds an explanation why you do A)).
I do A if B h