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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2021-04-08</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001637715</issuerCik>
        <issuerName>Reneo Pharmaceuticals, Inc.</issuerName>
        <issuerTradingSymbol>RPHM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001648895</rptOwnerCik>
            <rptOwnerName>Seltzer Stacey Denenberg</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RENEO PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>12230 EL CAMINO REAL, SUITE 230</rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92130</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Vineet R. Jindal, Attorney-in-Fact</signatureName>
        <signatureDate>2021-04-08</signatureDate>
    </ownerSignature>
</ownershipDocument>