According to the sources provided, the patent for Yervoy (ipilimumab) is set to expire on March 25, 2022 [1][2]. Yervoy is a blockbuster drug that is used for the treatment of melanoma and other cancers. It is manufactured by Bristol-Myers Squibb and was approved by the FDA in 2011 [3]. The expiration of the patent for Yervoy is expected to have a significant impact on the pharmaceutical industry, as it will open the door for generic versions of the drug to be produced and sold at a lower cost [2][3]. The expiration of the patent for Yervoy is also part of a larger trend known as the "patent cliff," which refers to the expiration of patents for many blockbuster drugs over the next few years [2]. This trend is expected to have a significant impact on the pharmaceutical industry, as it will create opportunities for generic drug manufacturers to enter the market and compete with brand-name drugs [3].

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/YERVOY
[2] https://www.fiercepharma.com/special-report/top-15-blockbuster-patent-expirations-coming-decade
[3] https://scrip.pharmaintelligence.informa.com/SC146175/The-Next-Big-Patent-Cliff-Is-Coming-And-Time-Is-Running-Out-To-Pad-The-Fall