totally agree, unite forces!!

This should probably be a high priority feature, after all Protonmail should be an email service before many other things (calendar, drive, etc).

Sadly, I wouldn't say this is Protonmail's fault, after all they allow an easy use of PGP:
https://protonmail.com/support/knowledge-base/how-to-use-pgp/

but yea, it'd be awesome to see an automatic sharing of keys between protonmail and tutanota (or any other encrypted email service) son that users fron each service could send emails to each other easily.

Would like this too. Governments spy on emails as they are in transit and this can help ProtonMail users communicate easily with other encrypted email providers.

I would like to see ProtonMail, Tutanota, Criptext, and all the other PGP email providers work together on a system that will allow users to send and recieve emails from one another without having to configure the PGP in the email. Just like how you can send an email between two ProtonMail addresses and ensure the email is encrypted in transit.

When I send a email to non ProtonMail users such as Tutanota and Criptext, the email will not be encrypted in transit which can be read by government agencies unless I setup PGP.

Obviously this makes perfect sense, the rational why to do it holds up and then.....

......the makers find objections, problems, excuses. NO YOU CAN'T HAVE THIS SILLY PEOPLE!

This is an awesome idea! Not just with TutaNota, but also other providers that offer encrypted email (if there are any). They all use PGP for encryption, so this wouldn't be too complicated.