  Unifying relations of amplitudes are elegant results in flat spacetime, but
the research on these in (A)dS case is not very rich. In this paper, we discuss
a type of unifying relations in (A)dS by using Berends-Giele currents. By
taking the flat limit, we also get a semi-on-shell way to prove the unifying
relations in the flat case. We also discuss the applications of our results in
cosmology.
