A more thorough explanation:

Cross-Licensing is an agreement between two or more patent holders to share their patents with each other. This agreement is made to avoid any legal disputes that may arise due to conflicting patents. It helps inventors to commercialize their innovations and undertake new research.

For example, if Company A has a patent for a technology that Company B needs to use in their product, and Company B has a patent that Company A needs to use in their product, they can enter into a cross-licensing agreement. This way, both companies can use each other's patented technology without any legal disputes.

Cross-license agreements have been frequently litigated in antitrust law. The court will analyze the cases that involve cross-license agreements under the Rule of Reason, in which both the anti-competitive and the pro-competitive effect of the agreement will be considered. Generally, such agreements are pro-competitive.

For instance, in the case of Feinsod v. Stiefel Labs., Inc., the court found that the cross-license agreement between the two companies was pro-competitive and did not violate antitrust laws.

In summary, cross-licensing is an agreement between patent holders to share their patents with each other to avoid legal disputes. It helps inventors to commercialize their innovations and undertake new research.