As of now CSF has some features not implemented in Imunify360 (i.e. block by port, process tracking, directory watching and some email-related features). According to this info, you can make the decision whether to use CSF together with Imunify360 on the server. Actually, if you are using CSF only for web traffic, you can safely disable it and run Imunify360 alone.
Thank you for your answer. CSF and Imunify360 could be used together, there are settings for better integration and performing. Yet, we're developing features that are missing in Imunify360 so it will allow replacing the CSF completely in the nearest future.