This is the opening I'm referring to:
[fen ""] 1.d4 Nf6 2.Nf3 e6 3.g3 b6 4.Bg2 Bb7 5.O-O Be7 6.c4 O-O 7.Nc3 Ne4 8.Bd2!?
The other white book moves at this point seem sensible
8.Qd3, or even
8.Nxe4 (which seems to almost always draw). I'm unsure about
8.Bd2, as it seems to give up the bishop pair (and
8...Nxd2 has been played, e.g., Gelfand vs. Radjabov, 2017) and it puts the bishop on a fairly modest square, but it's listed as having 1500+ master games at LiChess.
Question: Why is 7...Ne4 8.Bd2 such a popular line in this variation of the Queen's Indian Defence?
The most popular continuation on LiChess is the following:
[fen ""] 1.d4 Nf6 2.Nf3 e6 3.g3 b6 4.Bg2 Bb7 5.O-O Be7 6.c4 O-O 7.Nc3 Ne4 8.Bd2 f5 9.d5 Bf6 10.Rc1 Na6 11.a3 Nac5 12.b4 Nxc3 13.Bxc3 Ne4 14. Bxf6 Qxf6