Humanitarian and Compassionate (H&C) Grounds apply to foreign nationals who have exceptional cases who would otherwise not qualify for permanent residency in any other class. Immigration, Refugees, and Citizenship Canada (IRCC) will assess H & C applications, on a case-by-case basis, and consider the compelling factors for each case.
You may only ask for H & C grounds if you are applying for permanent resident status in Canada, or for a permanent resident visa abroad.