Additional Study Information: The purpose of this study is to find out if the experimental product, axi-cel, is safe and effective in treating your lymphoma, compared to standard of care (SOC) therapy (chemotherapy), which includes either R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone) or DA EPOCH R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab). The experimental treatment would involve removing some of your immune cells, genetically engineering those cells to identify cancer, receiving additional therapy while you wait for those cells to be manufactured, and then infusing those cells back and assessing the effect on your cancer. The experimental product, axi-cel, is not approved by the US Food and Drug Administration (FDA). Participants in both treatment arms will be followed for up to approximately 5 years after being randomized into a study treatment group (randomly assigned, like the flip of a coin).