Tanks (Also called armor) are armored vehicles with treads, that often make up the backbone of offensive taskforces. Historically, Tanks first appeared during the Great World War I, earning their name from the water tanks they were disguised as. Generally, tanks have one or more cannon(s) which did good damage to structures, vehicles, other tanks, but had difficulty accurately hitting smaller infantry, and therefore dealt less damage via shrapnel. However, as even light tanks weigh several tons, these machines can easily crush infantry by running them over. Also, several tanks substitute other weapons, such as flamethrowers or lasers, for the cannons.
Against their armor plating, small-arms fire is generally ineffective; however rockets and missiles do greater damage. Also, few tanks have any anti-air defense, and those that due are often still incapable of adequately defending themselves against air attacks. As vehicles, tanks are susceptible to EMP interference as well.
Early on, tanks were generally classified by weight, lighter tanks being faster and cheaper, but weaker. Unless in superior numbers (which, considering their greater efficiency, was achievable), light tanks could not defeat medium tanks. Medium tanks could not defeat easily heavy tanks, and heavy tanks could not easily defeat Super Heavy tanks such as the Mammoth Tank. Modern warfare use the term Main Battle Tank (MBT) to refer to tanks used primarily used by one side.
The USSR and GDI were known for their wide use of tank technology.
Great World War II
See: Tanks (Red Alert)
First Tiberium War
In a strategic twist, GDI chose to follow design philosophies from both sides of GWWII. GDI retained the classic M1 Abrams medium tanks, however, as much of the research was lost, experienced a significant delay in the production of Mammoth tanks, which required significant redesigns for the conflict and only appeared towards the end but was useful. GDI tanks required a lot of anti-infantry support that involved MLRS', APCs and Humvees.
Nod, choosing efficiency and speed, used M2 Bradley Fighting Vehicles. Unable to compete with GDI in terms of strength, Nod chose to build highly specialized tanks to supplement their numerous Bradleys. The "Ezekiel's Wheel" Stealth Tank had an onboard stealth generator, allowing it to be almost invisible to the human eye, except when firing it's missiles. The "Devil's Tongue" Flame Tank was a specially designed tank fitted with flamethrowers, which caused tremendous damage to structures and infantry. The Brotherhood also built their Second version of the Light Tank, for use by the Special Forces group, the Black Hand.
Second Tiberium War
During the twenty first century, GDI chose to phase out their existing tank arsenals in favor of Disruptor tanks and Mechanized walkers, such as the Titan and Mammoth Mk. II. To note, a few abandoned Mammoth Tanks ended up in the possession of the Forgotten, a few belong to GDI during the testing of the new walkers and during the assault on Cairo, however, the antiquated systems of these tanks meant that they were no longer as dominant as they once were.
Nod continued tank advancement, incorporating more advanced technology on their stealth tanks. Nod's advent of subterranean and burrowing technology also resulted in the advancement of two new tank types; The "Devil's Tongue" had been upgraded to burrow underground, making it a perfect surprise attack unit, while the Tick Tank could bury itself to serve as a stationary anti-tank turret.
Third Tiberium War
After the Second Tiberium War and Firestorm Crisis, GDI chose to scrap their mechanized walkers, which was criticized by many who viewed it as a financially motivated decision. With the only walker still in service the Juggernaut, GDI returned to classic tank designs, returning to the medium tank design for the Predator Tank, the Shatterer hovertank, the Slingshot AA Tank and bringing back their classic Mammoth Tanks in the form of the Mammoth 27. Both tanks could be upgraded with Railguns to increase their lethality. The Steel Talons, being the die-hard conventionalists they are, still use walkers.
To fight Tiberium in the Red Zones the GDI subfaction ZOCOM constructed a massive tank that harvests Tiberium and is heavily armed and armored codenamed the MARV and was GDI's epic unit in the war but three of them were destroyed by Nods epic unit the Redeemer.
Nod's Tank arsenal in the Third Tiberium War also brought back older designs. Due to problems with the subterranean technology, Tick Tanks were replaced by a new, faster Scorpion Tank; which could be upgraded with dozer blades to increase armor and allow the tank to crush Land Mines and heavy infantry, and laser capacitors based on the Obelisk of Light, increasing their firepower. The newest incarnation of the Nod Stealth tank was faster and more heavily armed than before, and the update to the Devil's Tongue allowed for heavier armor at the cost of burrowing ability. Also, both specialized tanks along with Beam Cannons and Attack Bikes could be "honor" vehicles to an Avatar Warmech. While the tanks would be destroyed and crews would be killed, the Avatar would benefit from stealth generators to a flamethrower.
The Scrin, though obviously not basing their technology on terran tank development (They could hover), had two vehicles that resembled human tanks. The first, the Seeker was a Scrin scout vehicle, capable stealth detecting and engaging both air and ground targets. The second, the Devourer Tank, classified as a Main Battle HoverTank (MBHT), was capable of absorbing tiberium to add range and power to its energy cannon (and was rumored to be created as a sadistic mockery by some). However, despite being from a race with incredibly advanced technology, Scrin tanks are roughly on the same playing field level as human tanks.
Fourth Tiberium War
With mechanized walkers became all the rage again by the 2070s, GDI widely replaced some of their tanks with Walkers, save the 4th generation Mammoth Tank, Reflector Tanks and Hunter Tanks. The Sheppard Tank is only available to the Support Crawlers while the Spartan Tanks can only be used by the Defense Crawlers.
Nod, being the hit-and-run faction at its core and in spite of Avatar upgrades, still uses some tanks, such as the next-generation Flame and Stealth Tanks. The Scorpion tank can now take on Mammoth Tanks and defeat even the most strongest Crawlers.