Cygnus OB2 is the closest massive star forming region hosting thousand OB stars to the Sun (1450 pc). It represents the best target to study how OB stars affect the star formation process, protoplanetary disk evolution and the evolution of the parent molecular cloud its surroundings. We obtained deep optical observations in r', i', and z' bands with the 10.4m Gran Telescopio Canarias OSIRIS camera, and performed an X-ray survey covering about 1 square degree with Chandra's ACIS-I (the 1.08 Msec Chandra Cyg OB2 Legacy Survey). These observations, combined with existing deep infrared and optical data of this region (from IPHAS, SDSS DR8, 2MASS/PSC, UKIDSS/GPS, and the ''The Spitzer Legacy Survey of the Cygnus-X Region'') allow us to select the cluster members down to sub-solar masses, and to analyze in detail the different effects that the radiation from OB stars have on the surrounding young stellar population, including triggering of star formation, externally induced disk photoevaporation, and dissipation of protostellar cores. In this contribution, we present the first results obtained from our combined survey: the selection of disk-bearing cluster members, the study of their evolutionary status and of the morphology of the association.