In the wake of rejoicing over the PlayStation 4’s input lag fix for Tekken 7, SRK forum member WAZAAAAA (with the help of Hardcore) discovered that there is still a wall between you and your inputs on PC.
It may only be 1 frame in size, but that one frame is potentially the difference between you blocking some lows on reaction or not. With that in mind, this Duo developed a tool to remove this frame of input lag from the PC version. You can read more about their tests to prove the existence of this input lag, overview of the tool, and their future plans for it here.
Source: WAZAAAAA (SRK Forums)