CDKN1A and obesity due to melanocortin 4 receptor deficiency: On the contrary, in the HFD‐induced obesity, exercise reduced the level of p21Cip1 in obese animals after subgroup analysis by the disease states, including aging and obesity, while more studies are required to understand its effects on senescent cells in aged animals (Jang et al., 2019; Schafer et al., 2016).