"NTU RGB+D 120" is the extended version of the "NTU RGB+D" dataset. It was introduced in TPAMI 2019 paper [PDF].
This dataset contain RGB videos, depth map sequences, 3D skeletal data, and infrared (IR) videos for each sample. Each dataset is captured by three Kinect V2 cameras concurrently.
Details about NTU-120 dataset can be found on the official NTU-120 github repository here