From Longman Dictionary of Contemporary Englishbe in line for something/be in line to do somethingbe in line for something/be in line to do somethingPROBABLYto be very likely to get or be given something I should be in line for promotion soon.first/second/next etc in line for He must be first in line for the editor’s job. → line
Examples from the Corpus
first/second/next etc in line for• As a lad, Cloud and his two brothers were next in line for the Frankish throne. 