<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-11-08</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001217234</issuerCik>
        <issuerName>CareDx, Inc.</issuerName>
        <issuerTradingSymbol>CDNA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001339358</rptOwnerCik>
            <rptOwnerName>Cohen Fred E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAREDX, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3260 BAYSHORE BOULEVARD</rptOwnerStreet2>
            <rptOwnerCity>BRISBANE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94005</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to Purchase Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>12.40</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2017-11-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10948</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2024-06-19</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10948</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to Purchase Common Stock</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.49</value>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2017-11-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6679</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2024-11-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6679</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6679</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares underlying the cancelled option were vested and immediately exercisable.</footnote>
        <footnote id="F2">On November 8, 2017, pursuant to the offer by CareDx, Inc. (the &quot;Company&quot;) to exchange certain outstanding stock options for new options as more fully described in the Schedule TO-I, filed with the Securities Exchange Commission on October 12, 2017, as amended and supplemented on October 24, 2017 and November 9, 2017(the &quot;Exchange Offer&quot;), the Company cancelled a stock option for 10,948 shares granted to the reporting person on June 19, 2014. In exchange for such cancelled stock option, the reporting person received a new stock option for 6,679 shares.</footnote>
        <footnote id="F3">Represents a stock option granted pursuant to the Exchange Offer (the &quot;New Options&quot;).</footnote>
        <footnote id="F4">The exercise price per share equals the closing price per share of the Company's common stock, as quoted by NASDAQ, on November 9, 2017.</footnote>
        <footnote id="F5">The New Options are scheduled to vest in three equal installments based upon the Company's achievement of certain performance goals as follows: (i) one third of the New Options vest upon the Company's determination, which has been reviewed by the Company's independent registered public accounting firm, that the Company has achieved $10 million of total cumulative sales of Allosure, its proprietary next-generation sequencing-based test to detect donor-derived, cell-free DNA after transplantation, commencing after the completion of the Exchange Offer, (ii) one third of the New Options vest upon the Company's determination, which has been reviewed by the Company's independent registered public accounting firm, that the Company has achieved quarterly revenues of at least $18.75 million for two consecutive fiscal quarters commencing after the completion of the Exchange Offer,</footnote>
        <footnote id="F6">(Continued from Footnote 5) and (iii) one third of the New Options vest in the event the closing sales price of the Company's common stock is at or above $5.00 per share, as quoted by NASDAQ, for 10 consecutive trading days after the completion of the Exchange Offer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Peter Maag as attorney-in-fact for Fred E. Cohen</signatureName>
        <signatureDate>2017-11-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
