This claim is false. After visiting the X account that posted the picture, I concluded that they are not a reliable source. The account is not ran by an organization, but rather an individual who mainly posts about pop culture. Many of their posts are satirical and they do not have many followers. They likely captioned the Chris Evans with the intention of being funny.
There have been numerous fact checks conducted on this post already, including ones from Misbar.com and Reuters. Both fact checks link the origin of the post which is from the Flickr account of the Office of the Chairman of the Joint Chiefs of Staff for Public Affairs.
The caption revealed the true context behind the image. The photo was taken on December 5, 2016 in Turkey. Chris Evans and other celebrities met with service members at Incirlik Air Base. The groups was on tour for the United Service Organizations which arranges for celebrities to visit U.S. military personnel serving around the world. The other man in the picture, Marine General Joseph F. Dunford Jr., is wearing a uniform that clearly labels him as U.S. Air Force.
This Flickr account proves the claim is false because the image was taken in 2016 and has no ties to the current Israel Gaza conflict.
This is an example of false context because while the picture is real, the X user re-circulated it out of its original context.