In the scene showing Mahalia Jackson's debut at Carnegie Hall, the song she sings is "How I Got Over," which was composed by Clara Ward, her chief rival as the #1 Black female gospel singer.
Before the concert at Carnegie Hall, Mildred Falls [Joaquina Kalukango] soaks her hands in hot water. This was also a strategy used by classical pianist Glenn Gould (1932-1982), to warm up the joints in his hands before playing piano.