Dm7

The 'axis' progression (vi–IV–I–V)

Here Dminor-7 is the vi chord of F major — the most common loop in modern pop.

Minor ii–V–i

Dminor-7 acts as the tonic and the chord everything resolves to.

I–V–vi–IV

Dminor-7 is the emotional turn in the middle of the loop.