  Measurement of the universe expansion rate through the cosmic chronometers
proves to be a novel approach to understanding cosmic history. Although it
provides a direct determination of the Hubble parameters at different
redshifts, it suffers from underlying systematic uncertainties. In this work,
we analyze the recent cosmic chronometer data with and without systematic
uncertainties and investigate how they affect the results. We perform our
analysis in both model-dependent and independent methods to avoid any possible
model bias. In the model-dependent approach, we consider the $\Lambda$CDM, wCDM
and CPL models. On the Other hand, since the Gaussian process provides a unique
tool to study data including a non-diagonal covariance matrix, our
model-independent analysis is based on the Gaussian process.
