Only if you’re trying to show the CMB and galaxies in the same image. Since doing so would be misleading as to the brightness of the CMB, that seems like a feature, not a bug.
No, if you insist on a uniform colormap that includes 0K (or whatever measurement you're showing the CMB with) then there's absolutely no way to make the CMB visible. The average temperature is 2.72548 K with variations on the order of 0.00057 K. Its incredible uniformity is one of its more important features.
