Control a second lamp with a motion sensor lamp?

There are various providers, Steinel offers e.g. SL (Slave) lamps, in addition to those with motion sensors. Then one motion sensor controls both.

It should (at least in the PRO series) even work in a way that both have a motion sensor, and as soon as one of them triggers, both lamps turn on. But you better check the details yourself or get advice.

Sometimes the BWM output is led to a separate terminal on the terminal block of your lamp. From there, you only need one cable to your second lamp. Then it works.