  Recent data seem to suggest a preference for the evolving dark energy (DE).
However, if the case is actually so, and not caused by unknown systematics in
data, it might impact our understanding about our Universe in an anomalous way
due to the shifts of some primary parameters. As an example, we present the
search for the primordial gravitational waves, based on the evolving DE. The
joint analysis of recent BICEP/Keck cosmic microwave background (CMB) B-mode
polarization data with Planck18 CMB, DESI baryon acoustic oscillations and
PantheonPlus data shows that the bestfit tensor-to-scalar ratio is
$r_{0.05}\sim 0.01$, and the lower bound of $r_{0.05}$ is $\sim 2\sigma$
non-zero.
