So despite already playing a Kree villain in Captain Marvel, Gemma Chan will now be Sersi as well in the MCU. Between Captain Marvel and Crazy Rich Asians, I haven't seen enough of Chan to say how good an actress she is, but she has a good look for Sersi.
So apparently Dane Whitman, the Black Knight, will appear in The Eternals movie and Kit Harrington will star in the role. Harrington is a big enough star that it makes me think Marvel has significant plans for the character down the line. Personally, I think the first Eternals movie has so much to explore in the Eternals mythology - a big cast of Eternals + Deviants + Celestials - that stuffing the Black Knight into the movie is too much, but we will see.
Seeing the Black Knight added to the Eternals and the MCU makes me wonder...WHERE'S MY HERCULES?!!!
I hope Hercules appears in Thor: Love and Thunder because he's one of my favorite Marvel heroes and he would fit in the MCU.