The nature of dark energy is one of the big puzzling issues in cosmology. While $\mathrm{\Lambda }\mathrm{CDM}$ provides a good fit to the observational data, evolving dark energy scenarios, such as the CPL parametrization, offer a compelling alternative. In this paper, we present a Bayesian model comparison of various dark energy parametrizations using a joint analysis of cosmic microwave background data, DESI baryon acoustic oscillation measurements, and the PantheonPlus (or Union3) Supernovae type Ia sample. We find that while the $\mathrm{\Lambda }\mathrm{CDM}$ model is initially favored over a constant $w\mathrm{CDM}$ model, the CPL parametrization is significantly preferred over $w\mathrm{CDM}$, reinforcing recent evidence for an evolving dark energy component, consistent with DESI Collaboration findings. Crucially, when testing higher-order CPL extensions, the so-called ${\mathrm{CPL}}^{+}$ and ${\mathrm{CPL}}^{++}$, our Bayesian analysis shows that the observational data do not favor these more complex scenarios compared to the standard CPL. This result indicates that adding excessive complexity to the CPL form is unwarranted by current observations. Interestingly, similar to the CPL parametrization, alternative two-parameter forms, specifically $w_{de}(a)=w_0+w_b(1-a{)}^2$ and $w_{de}(a)=w_0+w_c(1-a{)}^3$, yield a better fit to observational data than the standard $\mathrm{\Lambda }\mathrm{CDM}$ cosmology. Our results challenge the necessity for overly complex CPL extensions and confirm that well-chosen two-parameter $w_0{w}_a$ parametrizations effectively capture DE evolution with current cosmological data, supporting the recent signals for dynamical dark energy by DESI Collaboration.

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• Cosmological parameters
• Cosmology
• Dark energy