ok so im facing a full stealth team and my Deadshot has the ability that says

UP CLOSE, AT RANGE, NO DIFFERENCE: Improved Targeting: Ignores Hindering Terrain

since he ignores HT. if a person is in it and hiding in stealth. wouldnt DS's ability counter stealth so he can hit them?

Short answer: Stealth doesn't stop Deadshot. Fire away!

Longer answer:
I don't like saying he "counters" Stealth, because countering powers is a specific game effect and that's not what is going on here.

When Deadshot draws a line of fire, he ignores hindering terrain; think of it as the hindering terrain isn't even there.

Stealth does its thing when a line of fire crosses hindering terrain, so Stealth is worthless when Deadshot is attacking. No Stealth, no +1 Defense bonus against ranged attacks, etc.

Since Deadshot ignores hindering terrain for line of fire, none of his lines of fire are hindered, ergo stealth doesn't do anything.

Shoot that Batman!

its actually a mix of batman and the federation lol i was aiming at scott lol

When a character ignores hindering terrain with improve targeting, they are treating it like clear terrain for line of fire purposes.