“Thy Kingdom Come” is a worldwide prayer movement that invites Christians around the world to pray from Ascension (Thursday, 21st May) to Pentecost (Sunday, 31st May). “Since its launch by the Archbishops of Canterbury and York in 2016, Christians from 172 countries and 65 denominations have taken part in praying for friends and family to come to faith in Jesus Christ. These days have always been full of expectation and anticipation. As the Lord ascended, he promised the gift of the Holy Spirit to enable the disciples to be witnesses. As they waited for the promise to be fulfilled they devoted themselves constantly to prayer (Acts 1:14). So, the renewed call across the church is to set these days apart to pray and each individual to pray for 5 people to come to know the love and peace of Jesus Christ.”
You can find a great range of resources here