Creating a systematic review protocol is an important step in the planning process for your review. A review protocol is beneficial for a number of reasons:
Your review team should strongly consider registering your protocol with a systematic review protocol registry. Doing so will notify other researchers of your work, which can reduce the possibility of duplicate projects.
In the early stages of your own project, you should also consider searching these registries for review protocols. Doing so will allow you to see if any researchers have ongoing projects on your topic or a similar topic. Also, seeing a completed review protocol (on any topic) could help with constructing your own.