High-energy physics (HEP) experiments have developed millions of lines of code optimized to run on traditional x86 systems. However, leadership-class computing facilities and traditional data centers use new accelerator architectures, such as GPUs. HEP experiments are now faced with the untenable prospect of rewriting millions of lines of code. This task is made more challenging by the architecture specific languages and APIs promoted by the different vendors. The Portable Parallelization Strategies team of the HEP Center for Computational Excellence is investigating Kokkos, SYCL, Alpaka, etc. as potential portability solutions using representative use cases from DUNE, ATLAS, and CMS experiments.