The Comment and comment macros are regular macros that does not produce any output. Capitalization is explained at: Section "Block vs inline macros".
You will therefore mostly want to use it with a literal argument, which will, as for any other macro, ignore any macros inside of it.
Before comment.

\Comment[[
Inside comment.
]]

After comment.
which renders as:
Before comment.
After comment.
And an inline one:
My inline \comment[[inside comment]] is awesome.

\comment[[inside comment]] inline at the start.
which renders as:
My inline is awesome.
inline at the start.

Ancestors