Multiple studies analyzing CMB polarization have recently reported evidence for cosmic birefringence, which refers to a rotation of the polarization plane of photons during their propagation. This signal violates parity symmetry and suggests the presence of extremely light pseudoscalar fields, such as axion-like particles. Such fields are potential candidates for dark matter or dark energy. In this seminar, we discuss the current observational status of cosmic birefringence, its implications for searches of dark sectors, and future prospects.