Two-dimensional systems in modulation-doped Si/SiGe and Ge/GeSi heterostructures have been the main topics for quantum physics for decades. However, those heterostructures suffer from gate leakage and dopant fluctuations, which leads to device instability of quantum dot devices. Recently, two-dimensional systems in undoped heterostructures have been developed with record-high mobility and extremely low metal-insulator transition density. Strong spin-orbit interaction (SOI) was discovered in undoped Ge/GeSi heterostructures as well. By top gating this undoped structure, the system could enter the ballistic spin transport regime, which paves the way for silicon-compatible spintronic devices such as spin FETs. In this talk, the material growth and transport properties of two-dimensional electron/hole gases in undoped Si/SiGe and Ge/GeSi heterostructures will be reviewed with unique surface tunneling introduced. Preliminary results on SOI in undoped Ge/GeSi heterostructures will also be presented.