Massive neutrinos play a crucial role in cosmology, influencing the evolution of cosmological perturbations and providing insights into neutrino masses. Experimental results on neutrino oscillations confirm non-zero neutrino masses but do not determine their absolute scale. Cosmological data, such as CMB anisotropies and large-scale structure distribution, offer complementary information on neutrino masses. The review discusses how massive neutrinos affect cosmological perturbations, summarizes current bounds on the sum of neutrino masses from various cosmological data, and explores future sensitivities to neutrino masses. It covers the cosmic neutrino background, the impact of massive neutrinos on cosmological perturbations, current observational constraints, and future experimental techniques. The review emphasizes the importance of neutrino masses in cosmology and their implications for dark matter and the universe's structure. It also addresses the role of neutrino oscillations in determining neutrino masses and the challenges in measuring absolute neutrino masses through terrestrial experiments. The review concludes with the significance of neutrino masses in understanding the universe's evolution and the potential for future observations to refine these measurements.Massive neutrinos play a crucial role in cosmology, influencing the evolution of cosmological perturbations and providing insights into neutrino masses. Experimental results on neutrino oscillations confirm non-zero neutrino masses but do not determine their absolute scale. Cosmological data, such as CMB anisotropies and large-scale structure distribution, offer complementary information on neutrino masses. The review discusses how massive neutrinos affect cosmological perturbations, summarizes current bounds on the sum of neutrino masses from various cosmological data, and explores future sensitivities to neutrino masses. It covers the cosmic neutrino background, the impact of massive neutrinos on cosmological perturbations, current observational constraints, and future experimental techniques. The review emphasizes the importance of neutrino masses in cosmology and their implications for dark matter and the universe's structure. It also addresses the role of neutrino oscillations in determining neutrino masses and the challenges in measuring absolute neutrino masses through terrestrial experiments. The review concludes with the significance of neutrino masses in understanding the universe's evolution and the potential for future observations to refine these measurements.