As I understood it, the map of the cosmic microwave background (CMB) corresponds to the time when photons decoupled from matter, making the universe transparent. In this sense, we might expect the CMB to be a limit to how far we can see.
Nevertheless, is it possible to say that we can look further than that? For example, if we look at the CMB fluctuations, or at the time-evolution of the CMB spectrum, can we infer/look beyond the time at which photons decoupled?
EDIT: as mentioned in a comment, what I was suggesting is that observing something other than electromagnetic radiation would allow to go further. The standard model does not give many options, and gravitational waves seems to be the best one.