I work (broadly speaking) in epidemiology. Within collaborations we often have to share sensitive data across institutions and are therefore likely to not share IT facilities. But the most often used options - bare e-mail or file hosting - are not secure, as they both work via a server that could potentially be exposed.
There are a handful of secure options around (ProtonMail or keybase.io, both working via encryption), but for those that trust open source projects the most and are familiar with a terminal I have written some basic instructions for asymmetric GPG encryption.