It's thought that Sane's deal expires in March 2020, given that she originally signed a three-year contract in March 2017. In addition, Kairi's current tag team partner, Asuka, is also working on a deal that ends soon.
Dave Meltzer commented on both wrestlers' situations on a recent episode of Wrestling Observer Radio. Regarding Asuka, he said that he had "heard no rumblings whatsoever of [her] leaving," and was "under the impression that she is very happy in this country," though that may not be the case for Sane, who has "definitely expressed interest in exploring other options."
As Meltzer notes, this doesn't mean that Sane is definitely going to leave WWE, though it isn't hard to understand why she might not feel 100% creatively fulfilled in the promotion, despite her current status as a pushed Women's Tag Team Champion.
It's hard to imagine a universe in which WWE don't extend a big-money offer to convince Sane to stay. Let's see if that happens.
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