Some would probably think he favors Sombra in some ways, like a parent that gives their youngest child more leeway than the eldest. The reality is that while on a mission (even an incredibly extended one, such as this), Widowmaker is much easier to read, despite her having very few emotions to read. The less he has to think about it, the easier it is, and that makes her an excellent team member.

Sombra is a wild child, someone he has to give some room. She doesn't respond well to being micromanaged, which, again? Not his style. Not to mention incredibly inefficient. So it all works out for everyone. Widowmaker's apparent concern about Sombra's intentions isn't something he's willing to spend too long worrying about, as long as he's aware that there just may be something lying beneath the surface. Just gotta keep on it.

While he doesn't doubt Sombra has her own agenda, he's always had a feeling that she'd get nothing out of screwing them over anyway.

"Glad you've both made up," he drawls, head tilting slowly like he's rolling his eyes with it. "Any other concerns?"