Influenza A (H1N1 and H3N2) and Influenza B (Yamagata and Victoria lineages) have circulated in humans for many years; a paucity of official reports of Influenza B Yamagata lineage virus infection in humans since 2020 supports that this lineage is not currently circulating at a high level among humans (you can read more about how these different viruses vary at https://www.cdc.gov/flu/about/viruses/types.htm ). Influenza viruses and SARS-CoV-2 both spread primarily by the respiratory route, and so many nonpharmaceutical measures taken to reduce the spread of COVID-19 (like wearing masks, increased social distancing, etc) also led to reduced circulation of influenza viruses during the pandemic (see more https://pubmed.ncbi.nlm.nih.gov/34292924/ ).