This book constitutes the proceedings of the 8th International Conference on Algorithms for Computational Biology, Al Co B 2020, was planned to be held in Missoula, MT, USA in June 2021. Due to the Covid-19 pandemic, Al Co B 2020 and Al Co B 2021 were merged and held on these dates together. Al Co B 2020 proceedings were published as LNBI 12099.The 12 full papers included in this volume were carefully reviewed and selected from 22 submissions. They were organized in topical sections on genomics, phylogenetics, and RNA-Seq and other biological processes.The scope of Al Co B includes topics of either theoretical or applied interest, namely: sequence analysis; sequence alignment; sequence assembly; genome rearrangement; regulatory motif finding; phylogeny reconstruction; phylogeny comparison; structure prediction; compressive genomics; proteomics: molecular pathways, interaction networks, mass spectrometry analysis; transcriptomics: splicing variants, isoform inference and quantification, differential analysis; next-generation sequencing: population genomics, metagenomics, metatranscriptomics, epigenomics; genome CD architecture; microbiome analysis; cancer computational biology; and systems biology.