How to render the field from custom block in node.twig I want to render the custom field from my block in node.twig. As I understand I have to expose the fields from Block to Node variables.

How to realize that?
A node should not have access to a block unless you've done something to add the block to the node. A block can have access to node fields, though (the reverse).

To do what you're talking about I would recommend adding that block to the node in some way. For example:

if you want to add a block as a field in a node:
https://www.drupal.org/project/fieldblock
I would normally use Display suite to then output this block as I want, where I want. But you can also access it via twig template at this point just as you would any other field.

if you're building with paragraphs:
https://www.drupal.org/project/paragraph_blocks