Another knowledge gap in the field of fatigue behaviour of SLM steels is their reaction to multiaxial cyclic loading condition. This situation is quite common in actual industrial cases, while the majority of the fatigue studies are carried out considering solely the uniaxial loading condition [3]. Even under uniaxial loading, complex geometries and notches might impose the multiaxial stress/strain states. This gap might result in the lack of understanding of the correct damage mechanism and inability of having a comprehensive fatigue life prediction in industrial applications. Additionally, development of more precise inspection methods to detect early stages of fatigue failure, as the one presented in [81], and improvement of the current methods is an important step towards increasing the reliability of AM metals, including SLM steels, which should be considered for future research.