I can use following code to remove  a field from Custom Filter:

@api.model
def fields_get(self, allfields=None, attributes=None):
    res = super(HrEmployee, self).fields_get(allfields=allfields, attributes=attributes)
    fields_not_search = ['id']
    for field in fields_not_search:
        res[field]['searchable'] = False
    return res

replace"['searchable']" by somewhat but I don't know what it is.

Thanks