Galaxy clusters are excellent natural laboratories to study the nature of gravity and test possible alternatives to the Concordance Model, at the edge between cosmology and astrophysics. I present recent results obtained on the mass profile of clusters, using the updated version of MG-MAMPOSSt, a code that reconstructs the mass distribution of clusters with kinematics and lensing analyses in modified gravity/Dark Energy frameworks. I will show the constraints obtained on the inner slope of dark matter profile using high quality imaging and spectroscopic data for the galaxy cluster MACSJ1206, down to the core. I will discuss alternatives to $\Lambda$CDM scenario and possible bounds in the parameter space that can be derived using a combination of kinematics and lensing analyses.
