The phrase "new commission" refers to a task or job that someone is given for the first time. It means that they have been assigned or appointed to do something they have not done before. Full definition
During the year, iconic works from the past return to the gallery alongside new commissions by acclaimed artists of the current generation. (artlyst.com)
This initiative will support nine new commissions for artists through 2019 working across cinema, stage, garden and galleries. (walkerart.org)
There is also a programme of new commissions of works made for the specific spaces. (tate.org.uk)