The team announced the moves Monday after the two helped the Giants get back into the playoffs for the first time since playing in the Super Bowl in 2012.
Cruz, 30, joined the Giants as a free agent in 2010, and his game-breaking ability at wide receiver helped them win their second Super Bowl under Tom Coughlin.
A knee injury and a calf problem caused him to missed most of the 2014 season and all of the 2015 season.
He returned last season but was limited to 39 catches and one touchdown, the only time he got to celebrate with his traditional salsa. He generally was the third option for Eli Manning behind Odell Beckham Jr. and rookie Sterling Shepard.
Cruz has made 303 catches for 4,549 yards and 25 touchdowns in his career.
"Victor is one of the great stories of the National Football League," general manager Jerry Reese said. "He came in here and earned everything that he's gotten. It has been amazing to see him grow from an undrafted free agent [out of UMass] to a Pro Bowl player and one of our go-to guys during the Super Bowl XLVI run. He will always be one of the great Giants."
Jennings, 32, joined the Giants as a free agent in 2014, after four seasons with the Jacksonville Jaguars, and one with the Oakland Raiders. In three years, he played in 40 games and rushed for 2,095 yards and 10 touchdowns. He also had 94 receptions for 723 yards and two scores. Jennings rushed for a team-high 593 yards last season.