I don't know if this brings anything real new, but maybe a hint or confirmation that Sigma is trying to get RF lenses on the market. Depending on how you interprets the conversation....
Spanish site https://www.photolari.com/ did an interview with Sigma CEO Kazuto Yamaki. The interviewer speaks Spanish which I don't understand. But with help from automatic subtitling I think the dialog is something like the following...
Photolari (P) ask about the situation or likelihood to get Canon RF lenses from Sigma, Kazuto Yamaki (Sigma) answers:
Sigma: Sigma's mission is to deliver lenses to as many customers as possible. And I'm very aware that there is a strong demand from Canon mirrorless users. I really appreciate such interest from customers. I cannot tell about future planning, but I really want to deliver such products in the future.
P: When such lenses hasn't yet arrived, is it because of Sigma or is it because of Canon?
Sigma: [Smiling, surely knowing why he's asked a question like that] Sorry, but I cannot comment on it [both laughing]. But what I can tell you today is that Sigma is very interested to satisfy the Canon mirrorless users' demand.