Nowadays, thanks to environmental awareness, there is a necessity for more lightweight, but still reliable products. Processing must also be efficient and reduce the use of resources. These two demands can both be met by using laser technology. Lightweight principles (material substitution and use of hybrid material compounds for reduced weight, fuel consumption and CO2 emissions) are the main objectives for using thin-walled constructions in the automotive industry. Due to the enormous potential of weight saving, and the consequential reduction of polluting emissions, the use of hybrid components made of steel and aluminum alloys is increasing steadily. For lightweight construction, different steel and aluminum materials with various thicknesses can be joined, depending on the dimensions and the individual functions of the workpiece. However, the combination of steel with aluminum in hybrid components requires a mixed material seam and in contrast to joining similar materials, thermal joining of steel and aluminum is still being fundamentally researched. A limited solubility in the binary system of iron and aluminum causes the formation of hard and brittle intermetallic phases during the liquid state of the joining components, and thus the strength and the formability of the dissimilar seam decrease. For a reliable, high strength seam, they must be reduced. For this material combination, laser beam brazing and laser beam welding are of great interest, being highly automatable as well as established processes in automotive engineering. Thus, both processes are currently topics of research at the Laser Zentrum Hannover e.~V., and aside from its common laser specific benefits, advantages are that welding provides a strong joint, whereas brazing offers higher formability. The latest results of these investigations will be presented.