Cosmic dawn is one of the least-explored epochs in the history of the Universe illuminated by the very first stars and black holes. One of the potentially powerful probes of cosmic dawn is the predicted 21-cm signal of neutral intergalactic hydrogen. The 21-cm signal is tied to the intensity of radiation generated by the first sources of light, and, thus, can be used to constrain process of primordial star and black hole formation as well as reionization. In my talk I will discuss modeling of the 21-cm line and synergies between this line and other high-z tracers.