What are the state-of-the-art cell-type RNA-Seq deconvolution methods? I would like to find the proportion of each cell-type in bulk RNA-Seq transcriptomics data. I am looking for some guidance on the following:

What are the state-of-the-art methods?
What are their assumptions? (e.g. do they assume that cell-type expression signatures are available in advance?)
I see a lot of people using xCell. There should also be papers systematically compare many different methods, which might interest you.