In this seminar we revisit several previous works concerning anisotropic differential equations, i.e. evolution equations in which the diffusion takes a different form within different space directions. Recently, in a joint collaboration with S. Ciani, we went back to these anisotropic PDEs, focusing on the singular ones, and started to work on some of their open problems. We’ll briefly discuss this ongoing project pointing out some of the difficulties one needs to address and overcome.