The theme for 2021 is Abiding in Christ, based around John 15:1-17.
The resources for the Week of Prayer for Christian Unity have now been published by CTBI
As you will see, as a departure from the usual practice, materials were prepared by the Monastic Community of Grandchamp in Switzerland & will use photos from the community (they have a beautiful wooden chapel with coloured glass windows). Their spirituality of prayer and silence is particularly apt during the pandemic.
Unfortunately, printed copies are not being published this year (but that will be a bonus for the environment!)