How to connect 2 points on different axis ?

How can I connect 2 endpoints (attached), that exist on different planes? I wish to connect them with an arc (e.g. 60 degrees like on the left side) , but I can’t figure how .

I would like to attach a Shapr3d file but i get the message I cannot because I am a new user …

Create a plane that contains the two lines you would like to connect. Add > Construction plane > type: Trough 3 points.

Once the lines are on the same plane you can draw your arc to connect them.