In 1996 (prior to the NeXT reverse merger) Apple and OSF started working on MkLinux which was Linux+Mach for PowerPC. Apple dropped it a couple years later.
The Walter Isaacson Steve Jobs biography doesn't have any mentions of Linux or Linus Torvalds FWIW.
But long term, given it is apple and ignore the sever part (which it should go now but not then), these are bad mix.
Still Steve did try to get linux as base (including talking with Linus) but even that is not right.
It turned out the strange bsd-cum-message based os work fine.