Yes, the hub is identical
Same 5x120 PCD and same 66.9 mm centre bore: wheels from Cadillac CT6 bolt on and centre on Buick Envision without rings. You still need to check the offset and tyres, detailed below.
≈: width estimated from the original tyre size.
Wheel by wheel: offset and tyres
Each original wheel from Cadillac CT6 is compared with the one from Buick Envision of the same diameter: how much closer the wheel gets to the shock absorber or how far it sticks out of the wheel arch, and whether the tyre keeps the same overall diameter.
- ✓
≈7.5Jx18 ET35 · 235/50R18 — Fits like the original
Compared with the original ≈7.5Jx18 ET37 on Buick Envision: shock absorber side −2 mm, wheel arch side +2 mm, tyre diameter −3.3 % : fit it with the original tyre size of Buick Envision (235/55R18), not that of Cadillac CT6.
Comparison for guidance only (estimated width). Check in detail
Before fitting the wheels
An identical hub is not enough: offset, width and diameter change the position of the wheel, and larger calipers can touch a smaller wheel. Original wheels often use bolts or nuts with a specific seat: keep the fixings intended for the wheel, with the thread of Buick Envision (Ecrous - 14x1.50), tightened to the torque shown on its vehicle page. Finally, check that the size is among the approved fitments for your vehicle. This comparison is for guidance only: have the fitting approved by a professional.
And the other way round: wheels from Buick Envision on Cadillac CT6?