  We present novel cosmological constraints based on a joint analysis of our
HII galaxies (HIIG) Hubble relation with the full Planck Cosmic Microwave
Background anisotropy spectrum and the Baryon Acoustic Oscillations (BAO)
probes. The HII galaxies span a large redshift range $(0.088 \le z \le 2.5)$,
reaching significantly higher redshifts than available SNIa and hence they
probe the cosmic expansion at earlier times. Our independent constraints
compare well with those based on the Pantheon compilation of SNIa data, which
we also analyse. We find our results to be in agreement with the conformal
$\Lambda$CDM model within 1$\sigma$. We also use our HIIG data to examine the
behaviour of the dark energy equation of state parameter under the CPL
parameterisation, $w = w_0+w_a \frac{z}{1+z}$, and find consistent results with
those based on SNIa, although the degeneracy in the parameter space as well as
the individual parameter uncertainties, when marginalizing one over the other,
are quite large.
