The following weapons were used in the film Monster Hunter (2020):

Assault Rifles

M4A1

At least one member of the UN special forces team (Diego Boneta) is armed with an M4A1 carbine fitted with a red dot sight and an AN/PEQ-15 ATPIAL.

Colt M4A1 with Aimpoint CompM2 reflex optic, Knight's Armament RAS railed handguard and vertical forward grip - 5.56x45mm

Link (Clifford "T.I." Harris, Jr.) is armed with what appears to be an M40A5 sniper rifle.

M40A5 sniper rifle with Harris bipod - 7.62x51mm NATO

Link aims the M40A5 with his scope eye closed for some strange reason.

Captain Natalie Artemis (Milla Jovovich) is seen manning and firing a General Dynamics GAU-17/A mounted on a Humvee gun turret. Curiously, it has a handlebar grip similar to the Terminator 2 minigun.

General Dynamics GAU-17/A, US Air Force version of the M134 Minigun - 7.62x51mm NATO

Captain Natalie Artemis mans the GAU-17/A.

Firing. Note the top-mounted handlebar grip which resembles the one on the T2 minigun.