Here's an example of a filter I'm using with several fields:
Sort(
Filter(
[@colMOCFilteredRecords],
If(
!IsBlank(txtMOCFilterID.Text),
txtMOCFilterID.Text in ItemNo,
true
),
If(
!IsBlank(txtMOCFilterCreatedBy.Text),
txtMOCFilterCreatedBy.Text in 'Header Submitted By',
true
),
If(
!IsBlank(txtMOCFilterCreatedFor.Text),
txtMOCFilterCreatedFor.Text in 'Header Requested On Behalf Of',
true
),
'Header Division' in cmbMOCFilterDivision.SelectedItems.Value,
If(
!IsBlank(txtMOCFilterTitle.Text),
txtMOCFilterTitle.Text in 'Header Title Of Change',
true
),
MOCStatus in cmbMOCFilterStatus.SelectedItems.Value,
'Header Change Classification' in cmbMOCFilterChangeClass.SelectedItems.Value
),
'Created On',
varMOCSortAscDesc
)