This particular lens is equipped with a Canon EF-M mount. Your filters need to have a diameter of 77 mm to fit this lens.
From JESSOPS
Samyang VDSLR 135mm T2.2 MK2 Cine Lens - Canon M-mount
Clifton Cameras
Samyang VDSLR 135mm T2.2 MK2 Lens - Canon M-Mount