https://www.science.org/doi/10.1126/science.abp8337
Forgot if I covered this paper before, but it uses viral phylogenic analysis to argue there were two zoonotic spillover events for SARS-COV-2. It is one of the biggest hurdles for the lab leak theory proponents to overcome. Early in the pandemic there were two distinct lineages of SARS-COV-2 called Lineage* A and B that arose. This paper is arguing that they most likely arose from two separate introductions. The chance of them arising from one introduction meanwhile is only 0.5% according to their analysis.
*Note when we talk about variants we are usually talking about variants of concern and strains that have unique characteristics on transmission/severity/etc. Lineages are just groups of genetically similar viruses with a common ancestor. They don't necessarily have unique characteristics, just different mutations. There are a lot of lineages of SARS-COV-2, but fewer variants of concern.