The GAP Assessment is required by NIST only.
It's
a subset of questions to determine your overall security posture, and
is a good starting port for any company doing a self assessment, or MSP
that is trying to determine the current status of a client company.
Regardless
of whether you're doing CMMC, the GAP Assessment is a good place to
start. All CMMC related Identifiers may not have GAP Assessment
buttons, but the majority do as they tie to NIST 800-171
There's two ways to handle the GAP Assessment. You can go through all the questions at once from the main dashboard:
Or you can address them directly in the identifier
Regardless
of how you choose to do it, filling it out in one section (the Full GAP
Assessment) or from the Identifier, matches it at both places. It's a
good starting point to determine Weaknesses as well, and where you need
to spend a lot of your focus.