We have recently discovered an exotic magnetic state developing at subKelvin temperatures in the Ce3+ pyrochlore stannate. The spin system of this compound is characterized by a thermally isolated Jz=1/2 Kramers' doublet at low temperature, providing effective spin 1/2 moments on a pyrochlore lattice. We have observed that these spins are characterized by a strong Ising anisotropy. The system does not order down to the lowest investigated temperature (70 mK). However, it develops a correlated regime for temperatures below 1 K, due to antiferromagnetic interactions one order of magnitude larger than the expected ferromagnetic dipolar couplings. We propose to explicitly measure the CEF scheme of Ce2Sn2O7 by inelastic neutron spectroscopy in order to confirm the picture of a thermally isolated Jz=1/2 Kramers' doublet at low temperature.