It is not always easy to fend off the zerg hordes when you are a highly evolved race of robots, so here is a general guide on how to win in PvT.
Generally you are going to want to start off with a low ground wall off into a fast expansion at your natural base location. The sim city from placing your pylon, gateway and cyber core on the low ground will enable you to hold off any early game ling floods as well as prove useful in the middle game in keeping zergling run bys at bay. The zerg for his part will probably grab a couple of bases and start droning up, but early aggression is also possible, so keep an eye out for ling elevators into your main, a quick baneling bust or even a roach ravager all in.
In terms of early game tech once your expansion is down and your cyber core is up, stargate is definitely a very popular opening. Oracles can pose a threat to your opponents economy, and just one queen isn’t really going to defend well against this harass because the oracle can snipe down too many drones before it is forced to flee so long as the protoss player remembers to focus fire. Holding shift and right clicking on a number of drones will ensure that no shot is wasted. You can also use your oracle to cast stasis ward in your opponent’s mineral line in order to slow down their mining. You generally want to build two oracles to start off, and then perhaps switch into a phoenix or a void ray to chase away any lurking overlords that might be used as a drop or just to scout. Make sure to take a mental note of any overlords spotted by your oracles and then dispatch one of your other air units to take them out.
Another very strong early game tech choice is dark templar drop. You don’t really expect to get too much done with the dts, although if you can snipe some drones or even a hatchery then obviously that is great but after the dt harass is shut down you can morph them into archons which can be very difficult for the zerg to deal with if they haven’t produced any roaches yet. Because archons have only shields they will regenerate eventually if you don’t let them die, so you can gain a good amount of value out of them with solid warp prism micro. You can also accompany your archon harass with zealot warpins to provide a little bit more meat to your threat in their main base. The zerg is going to want to focus down your warp prism with their queens, so make sure to micro it out of harm’s way and let the archons tank all the hits.
Adept pressure is a good idea in the early game, even if it is just a few poking in and trying to shave off some lings or a few drones. You don’t have to commit to a big adept all in, although that is one option if your opponent is being very greedy, but even just sending over a few adepts early on can give you some information like spotting an early roach warren which may indicate that your opponent is going to try a roach ravager all in. You can also preemptively shade away your adepts and then poke in to pick off a few lings while ideally losing only shields.
As you enter the mid game you want to develop a powerful ground army. Upgrades are crucial to extend the effectiveness of your troops, and you will want to tech up to psy storm fairly quickly. Psy storm is an extremely powerful spell in its own right, but also by forcing the zerg to disengage in order to dodge the storms your supporting ground units gain more effectiveness and do more damage relative to the enemy army. Sentries are an excellent support unit as well with guardian shield rendering the rest of your troops that much stronger and force fields are great at forcing the zerg to disengage and isolating a weak flank of the enemy army. Units from the robotics facility are also great at stomping on zerg hordes. Immortals can tank a lot of damage and basically crush anything on the ground, and colossi make a great addition to your army as well once you have upgraded extended thermal lance. Because the colossus range is so long you will be able to concentrate a lot more damage on the front line of the engagement, especially if you are fighting through a choke point.
Another powerful strategy in the mid-game is mass oracle. Originally invented by a Taiwanese player named Has, mass oracle found its way into the meta in 2017 and was used to great effect by a number of strong Korean protosses. Oracles are actually extremely powerful against zerg ground in the early middle game but they do have some hard counters like fungal growth and mutalisks or corrupters so you won’t be able to stay on this composition indefinitely. From here can either transition back to a ground army or go even further into sky toss and try to build a golden armada of carriers, void rays and mothership. You can’t usually go strictly mass carrier because if you do your opponent will simply make corrupters and chew through your army, but by mixing in some void rays you force them to try to a ground-based army composition. The problem with carriers is that they take a while to get online, so your opponent generally has an opening where they can kill you while you are building up your fleet. By maintaining a map presence with your oracles you can often tech up to carriers safely, as your opponents forces will be too busy fighting off your harass to march over and kill you. Stasis wards are also an excellent way to slow down an advancing hydralisk army while your capital ships and upgrades are still in production. Carriers have an upgrade that launches interceptors more rapidly and it is very important to research this if you are going for this composition.
You aren’t generally going to see too much muta play out of your opponents, because there are so many hard counters to mutas available to protoss players, such as phoenixes and archons. If you do see mutas make sure to get some phoenixes out asap but don’t over commit because your opponent probably will switch out of this tech very quickly.
The most popular zerg composition into the middle game is hydra / ling / bane and it is very powerful. These highly mobile units pack a ton of damage per second (dps) and will quickly jump on any morphing expansion nexus if you leave it undefended. Immortals and psy storm are your best answer to fending off this particular composition, and of course they must be supported by legions of gateway units. Adepts don’t have a ton of utility in the mid or late game and there is a shift now to where stalkers are becoming more popular that adepts even in the early game. Adepts are still a strong early game unit but you don’t really want to keep making them as the game goes on.
Another play you might see from a zerg in the middle game is a massive nydus attack into your main. The nydus worm is invincible while it is warping, so the zerg will generally send in their entire army and have the queens pop out first so they can transfuse the worm while the rest of their troops get into your base. If you stay on top of things you should be able to get your army in position before the zerg horde gets free reign to take out your production.
One of the strongest late game compositions for zerg is infestor, broodlords, corrupters and static defense. You don’t generally see too many ultralisks in ZvP although they can be used as a run by or as an addition to your army to tank a bit of damage. In order to fight against broodlords you are going to need some units that can target air. The most direct counter to broodlords is tempests. These long ranged flying siege units don’t pack too much of a punch, but broodlords don’t have a ton of hit points to begin with and being able to engage from a long distance is very nice. It is very difficult to fight brood lord with any sort of ground composition because the brood lings will mess up your pathing and provide a large buffer zone. Coupled with ground support like hydralisks and infestors the broodlings make