We consider a diffuse interface model for viscous incompressible two-phase flows where the effects of chemotaxis and mass transport are taken into account. The evolution system couples the Navier-Stokes equations for the volume averaged fluid velocity, a convective Cahn-Hilliard equation for the phase-field variable, and an advection-diffusion equation for the density of the chemical substance. This hydrodynamic system is thermodynamically consistent and it generalizes the Abels-Garcke-Gruen model for incompressible two-phase flows with unmatched densities. For the initial-boundary value problem in two dimensions, we report some recent progresses on the existence of global weak solutions and their propagation of regularity.