Innovative experimental techniques are needed to further search for dark matter. TPCs with optical readout are very promising candidates thanks to the 3D event reconstruction capability and the high sensitivity and granularity of sCMOS light sensors. The Cygno experiment is developing a TPC operated with He:CF4 at atmospheric pressure equipped with a GEM amplification stage that produces visible light collected by scientific CMOS camera and fast photodetectors. We present the performances of prototypes assessed exposing them to radioactive sources. We show that good energy and spatial resolution as well as discriminating power between nuclear and electron recoils is achieved in the keV energy range. Finally, we discuss the plan to build a 1m3 demonstrator expected to be installed and operated at LNGS in 2021/22. This experimental campaign aims at proving the scalability of such a detector concept to a bigger apparatus able to significantly extend our knowledge about DM and neutrinos.