2 matches remain and it is quite a difficult match for Dortmund, currently Milan is trying hard to get through to the round of 16, Milan has a big advantage because they are playing at home and in the previous match Dortmund and Milan both did not score goals and the match ended in a goalless draw, I think in the next match Milan will give more resistance and try to beat Dortmund at the San Siro stadium.
If PSG previously beat Dortmund at home, I think Dortmund will avenge that defeat when they host PSG because currently Dortmund is in high confidence after beating Newcastle twice.
It seems to me it is quite likely PSG will beat Newcastle on their own stadium, and if that is the case the key here will be the result of the match between Milan and Dortmund, If Dortmund wins then it is over and PSG and Dortmund will move to the next round, if there is a tie then Dortmund could probably move to the next round with another tie against PSG due to their goal differential, and if Milan wins then they will still need to get a win over Newcastle, but it should not be that difficult as at that point Newcastle should be eliminated already and will have no chance to advance to the next round or to move to the Europa league.