Hellfire for DPS classes ie DH etc can provide way more then an immunity amulet. Immunity amulets are for the zdps generally, but yes you can take the option of an ancient immunity amulet with GG stats generally fire or arcane with CC CHD mainstat socket. On a non ancient some people will reroll mainstat for ele dmg. Personally I ran a 10/98/749 socketed countess amulet up to grift 42 solo before I realized I simply had not enough damage to beat 43 or 44 without super good luck using cold maelstrom and I wasn't going to run the same tier 50 times in hopes of good pylons/rng. I finally crafted myself a nice cull the weak CC CHD socket dex amulet, was able to pickup steady aim +20% extra dmg, beat 3grifts higher solo to 45 and just recently did 46 in 11 so i know I can go one more atleast since new pylons are stupidly broken and grifts are a joke if you run THUD
you're awesome