In the comics, Ramonda is actually the surrogate mother of T'Challa, after T'Challa's mother died giving birth to him. She became the new wife of T'Chaka. She was abducted and abused for many years by a white supremacist, before being rescused by Black Panther and welcomed back into Wakanda.
Clearly things will be different in the Marvel Cinematic Universe; hearing that Bassett will play "mother of T'Challa" suggests that Ramonda's storyline wil be streamlined for the film. The question is where she will fit in the MCU timeline:
The most obvious scenario would be to have her play King T'Chaka's grieving widow in the film, who is there as support and guidance for T'Challa. However, if Ramonda is no longer alive or present in the current MCU timeline, her role would play out through flashbacks. Having Bassett's iron lady personality behind the queen of Wakanda would be great, as whe would be almost a greater force to be reckoned with than Black Panther himself.
If nothing else, we can all probably agree: Angela Bassett is the definition of "regal," so this is another good get for Marvel.
Directed by Ryan Coogler ("Fruitvale Station," "Creed"), "Black Panther" stars Chadwick Boseman in the title role alongside Michael B. Jordan, Forest Whitaker, Lupita Nyong'o, Danai Gurira, Daniel Kaluuya, Winston Duke, and Florence Kasumba. The film arrives in theaters on February 16, 2018.
Doctor Strange is now in theaters; Guardians of the Galaxy Vol. 2 – May 5, 2017; Spider-Man: Homecoming– July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; Avengers: Infinity War – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; and Captain Marvel on March 8, 2019.