A pretty straightforward film by Lee's standards. BlacKkKlansman is the story of a young but passionate black cop who infiltrates the KKK and uses a white (Jewish) stand-in for his face to face confrontations. Based on a biographical book, Lee sticks closely to the genre conventions.
That's a nice and easy way to honor the work of Stallworth, but it also makes for a slightly duller film. You don't need to know the history to predict how it all pans out and without Lee's stylistic flourish it's little more than a plot moving from beginning to end, at a pretty consistent pace.
Performances are nice though and while predictable, it's still quite fun to see how it all comes together. BlacKkKlansman isn't a bad film, it's just a little basic and by the numbers. The references to BLM and America's current political climate at the end of the film don't do much to change that.