Yes, it was there in 2017, and yes, it will be back for 2019 - but the TRD Pro trim wasn't available for 2018.
The thing that all the TRD Pro family have in common are the aluminum-bodied 2.5-inch TRD Fox Internal Bypass shocks.
The updates to the 2019 4Runner TRD Pro include a new roof rack, a 1/4-inch-thick front skid plate, 17-inch matte-black TRD alloy wheels, and Nitto Terra Grappler P265/70R17 A/T tires.
The snorkel is not meant to allow the Tacoma TRD Pro to travel under water, but as anyone with an internet connection knows, that is what makes the best videos. They're tuned for the specific characteristics of each vehicle by TRD engineers and offer improved dampening for on- and off-road driving situations.
The major exterior upgrade, and one that has all the Tacoma fans excited about this release, is the new TRD Desert Air intake that will save the 278 horsepower V6 engine from all the dust and silt that could foul it in time.
The Tundra TRD Pro uses Fox shocks and TRD springs for 2-inches of front lift. It has an upscale stereo, the Entune Premium JBL Audio with subwoofer amplifier and Integrated Navigation and App Suite, along with TRD Pro-branded floor mats and leather-trimmed seats. This truck has Rigid Industries fog lights, LED headlights, and LED accent lights. As a limited edition release, next year's TRD Pro will feature the same Fox Internal Bypass shocks, a wider array of paint choices, and a TRD Desert Air Intake option. Each wheel saves around 3.35 pounds of unsprung mass and comes wrapped in Michelin P275/65R18 all-terrain rubber.
The three vehicles all have the Toyota 36-month/36,000-mile warranty. The Fox shocks replace the external bypass tubes typically used on off-road race vehicles to manage damping pressure by compactly incorporating multiple bypass zones inside of the shock absorber, offering a cushioned, plush ride while still providing for bottoming resistance.