Collision avoidance in cloud
It has been a risk since flying began. About all you can do is listen on the radio for conflicting traffic and hope that you manage to see them when you are in cloud.
I recall a near miss in the Bindook area many years ago on the way to Sydney, going through culumus cloud and just as I was leaving one and before entering the next one an unannounced VFR traffic crossed at right angles to me at our altitude. That was my luck for the day.
Tmb