The Panasonic Lumix S 70-300mm f/4.5-5.6 Macro OIS is a telephoto zoom lens with the L mount. That means that although Panasonic would prefer you to use it on one of its S-series of full-frame mirrorless cameras, it can also be used on the Leica mount cameras from Leica and Sigma.
Leica currently has two full-frame L-mount cameras, the SL2 and SL2 S full-frame mirrorless cameras and two APS-C format L-mount cameras, the Leica TL2 and CL. Meanwhile, Sigma has the fp.