Short answer: Interface with Dr. Strange and Scarlet Witch, make way for Ghost Rider
There have been several Blade movies already, and the first is notable for being the first Marvel superhero movie of what's considered the current set of such movies (the first Marvel movie, superhero or otherwise, is largely considered to be Howard the Duck. And enough said about that.)
There have been three Blade movies so far and they... are done. Whatever loose threads were left hanging at the end are just going to be left untied.
Because Marvel is now doing three things with the Blade character. One is adding him to the MCU. One is recasting him with Mehershala Ali. And one is rebooting him entirely, with no plot threads connecting the character back to the Wesley Snipes movies.
They have done this before. While Daredevil is now in the MCU, we see from the latest Spider-Man installment that it's Charlie Cox's version (from the Netflix series-- which means that his fellow Defenders [Jessica Jones, Luke Cage, and Iron Fist] are also now in the MCU), not Ben Affleck's.
Similarly, Ed Norton's Incredible Hulk movie is in the MCU, but not Eric Bana's just-plain-Hulk one (or the Hulk TV show). Or the 1990 Captain America movie, or any of the three Fantastic Four movies... (not sure about X-Men). Anyway, the point is, ya gotta draw the line somewhere.
So the question before us is how to integrate Blade into the MCU. And the answer is going to be, I think, through the "magic" end of things*, which is to say via Dr. Strange.
His new movie, Multiverse of Madness, had some straight-up, demonic, horror-movie imagery in it. And I think that's the first time we have seen that, to such a gory degree.
So if we are putting a half-vampire vampire hunter-- which is what Blade is-- into the line-up, this is where he slots in. Wanda seems calmed down, but the Darkhold is likely eternal. Plus Agatha is still out there (and it was her, all along! Sorry, now the song is in your head.)
Since Dr. Strange is having to plunge into this world now, he might need some help. He's a wizard, not a hand-to-hand kinda guy, so having muscle like Blade at his side makes sense-- some things that go bump in the night may be magicked away, but some may just need to be bumped back harder.
This is good news for horror fans (if bad news for those who wanted to keep taking their kids to MCU movies). Because it opens up the potential for other characters from the creepier end of Marvel's work, like Ghost Rider. And Moon Knight (who has a show but is not in the movies yet).
In fact, Ghost Rider fans have smelled the brimstone in the air around Blade, anticipated that GR would follow, and have started asking that Nick Cage be allowed to continue playing him.
So it looks like at least one branch of the MCU is about to get super-creepy. Yay?/!
*And, yeah, there is magic in the MCU, but it seems to only relate to some characters, like Strange and Wanda and Thor. Meanwhile Tony Stark, Bruce Banner, and SHIELD work more with science, so the vampire/demon aspect of things seems less likely to be integrated into the MCU through those characters.