From 1d4chan
Look at their shit-eating grins. You know they just popped a whoopee cushion filled with all of the Galaxy's known STD's somewhere in the house.

There's a new kid in town and these shambling plague hosts are represented by the repugnant and varied Poxwalkers, each draped in scraps of clothing from their former lives. Poxwalkers — GW's copyright-friendly update of the classic Plague Zombie — are the new breed of Nurgle's rotting legions and sit somewhere between your basic Nurgle follower/cultist and Plaguebearers in Papa Nurgle's food chain. Crunch wise, Poxwalkers are smelly Grognards with pretty terrible stats and no shooting weapons, are slower than even Plague Marines, but can do Advance moves and get two base melee attacks. They also get the same Feel No Pain Disgustingly Resilient ability as Plague Marines so ignore any wound on a 5+, along with a 7+ armor save because that's a thing (since cover is a modifier now this can be improved). One of their only remarkable traits is that enemies slain in combat by Poxwalkers will themselves become a Poxwalker (sadly, they actually become a Poxwalker and not an undead version of themselves). Of course as awesome as that sounds that would probably need a whole ass PDF just to fit the chart of every possible zombified infantry unit and would almost certainly slow the game down massively as well as needing to be updated regularly and likely start all kinds of rules lawyering arguments. So, probably for the best that they went with the simple route.

Poxwalkers can be affected by a few buffs that turn them from a meh tarpit unit into one that's actually kinda good. The first is that if a Poxwalker unit contains 10 or more models it adds +1 to its attack rolls, making them hit on a 4. Another is Typhus; if he's within 6" Poxwalkers gain +1 S/T. Casting Miasma of Pestilence makes enemy shooting rolls -1, Putrescent Vitality gives them a further +1 S/T and all can be combined, along with Disgustingly Resilient ignoring wounds on 5+ and Curse of the Walking Pox adding models every time enemies are slain, to turn this into a shockingly effective blob unit. 20 of these will cost about the same as 5 Plague Marines (not counting Typhus' cost for the S/T boost). One of the Death Guard's Stratagems boosts them further by causing all non-Poxwalker infantry that die near them (including allies) to turn into Poxwalkers on death, so taking them with Cultists lets them become a massive tarpit that gains models faster than they can be killed off.

In the fluff, Poxwalkers are in fact Plague Zombies of a specific strain. The Walking Pox, as it's called, is spread by the sound of a Poxwalker's groans and has the especially cruel effect of preserving the victim's consciousness even after their death and transformation. This leaves the Poxwalker fully aware of its surroundings and condition, but incapable of controlling the actions of its decaying, increasingly mutated body. The Ordo Sepulturum think the Walking Pox may be a modified form of Nurgle's Rot, as even after the Poxwalker's death its flesh mutates in the same way as a Plaguebearer's.

GW has also made the dick move of not releasing them as a separate kit, so your only options of getting them are 20 from the Dark Imperium set (with some actual variety to the models) or 6 from the Ez-Build box. Consider that you'll probably want some extras on hand, for when your Poxwalker blob starts growing after some rounds of combat. Have fun. If you want some variety, grab some Skeletons or Zombies from the Warhammer Fantasy Age of Sigmar range.

Forces of the Death Guard
Leaders: Lord of Nurgle - Daemon Prince - Sorcerer - Chaos Champion
Malignant Plaguecaster - Plague Surgeon - Tallymen - Lord of Virulence
Troops: Biologus Putrifier - Blightlord Terminator - Chaos Spawn - Deathshroud
Foul Blightspawn - Noxious Blightbringer - Plague Marines - Possessed
Structures: Miasmic Malignifier
Vehicles: Chaos Land Raider - Helbrute - Plaguereaper - Predator - Rhino
Flyers: Storm Eagle - Stormbird - Thunderhawk
Spacecraft: Dreadclaw Assault Pod - Kharybdis
Blight Drone - Contagion - Defiler - Foetid Bloat-Drone
Myphitic Blight-Hauler - Nurgle Plague Tower - Plague Hulk
Plagueburst Crawler
Daemons: Beast of Nurgle - Nurgling - Plaguebearer
Auxiliaries: Cultists - Pestigors - Plague Zombie - Poxwalkers
Allies: Chaos Daemons - Chaos Space Marines