Stable microresonator Kerr soliton frequency combs in a III-V platform (AlGaAs on SiO2) are demonstrated through quenching of thermorefractive effects by cryogenic cooling to temperatures between 4 and 20 K. This cooling reduces the resonator s thermorefractive coefficient, whose room-temperature value is an order of magnitude larger than that of other microcomb platforms like Si3N4, SiO2, and AlN, by more than two orders of magnitude, and makes soliton states adiabatically accessible. Realizing such phase-stable soliton operation is critical for applications that fully exploit the ultra-high effective nonlinearity and high optical quality factors exhibited by this platform.