Electrically-charged armour or ECA:

Two shells holding a massive electrical charge, when a HEAT round hits the outershell the electrical charge is dissipated and repels the HEAT round, crew remain intact inside. Initial trials are very promising and if it becomes standard, then MBTs will be put in storage and tanks will become history. Armies will be using smaller faster vehicles fitted with ECA.

I suspect EMP will have some effect on it, as would a nuke of course.

So maybe this is another thing DX got right, because there are no tanks in Deus Ex 1, but there is plenty of EMP.