Only impeachment - as in a President can't pardon an impeachment. It is extremely cut and dry in the constitution in Article II, Section 2, Clause 1.

[...] and he shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment. The rest of that clause just deals with the military, militia, and executive departments.

Note - "Offences against the United States" means POTUS can only pardon Federal crimes - or crimes being tried in Federal Courts. So if someone commits a murder it could be a state charge or there could be circumstances that make it a federal crime. Maybe a bank robbery or kidnapping the FBI responds to, or a murder on a plane.

Only impeachment - as in a President can't pardon an impeachment. It is extremely cut and dry in the constitution in Article II, Section 2, Clause 1.

[...] and he shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment.

The rest of that clause just deals with the military, militia, and executive departments.