<SEC-DOCUMENT>0001209191-21-022480.txt : 20210322
<SEC-HEADER>0001209191-21-022480.hdr.sgml : 20210322
<ACCEPTANCE-DATETIME>20210322205812
ACCESSION NUMBER:		0001209191-21-022480
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210318
FILED AS OF DATE:		20210322
DATE AS OF CHANGE:		20210322

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Shah Nimish P
		CENTRAL INDEX KEY:			0001698082

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40215
		FILM NUMBER:		21762827

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		650-475-3734

	MAIL ADDRESS:	
		STREET 1:		7 BRYANT PARK
		STREET 2:		23RD FLOOR
		CITY:			NEW YORK CITY
		STATE:			NY
		ZIP:			10018

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Instil Bio, Inc.
		CENTRAL INDEX KEY:			0001789769
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				832072195
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3963 MAPLE AVENUE
		STREET 2:		SUITE 350
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75219
		BUSINESS PHONE:		(972) 499-3350

	MAIL ADDRESS:	
		STREET 1:		3963 MAPLE AVENUE
		STREET 2:		SUITE 350
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75219
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-03-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001789769</issuerCik>
        <issuerName>Instil Bio, Inc.</issuerName>
        <issuerTradingSymbol>TIL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001698082</rptOwnerCik>
            <rptOwnerName>Shah Nimish P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O INSTIL BIO, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3963 MAPLE AVENUE, SUITE 350</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75219</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>20.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-03-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>52000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-03-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>52000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option will vest in 36 equal monthly installments commencing on April 18, 2021, subject to the Report Person's continued service as a director through the vesting date.</footnote>
        <footnote id="F2">The Reporting Person is a member of VR Management, LLC (the &quot;Management Company&quot;). Under an agreement between the Reporting Person and the Management Company, the Reporting Person is deemed to hold the reported shares for the sole benefit of the Management Company and must exercise the reported shares solely upon the direction of the Management Company, which is entitled to the shares. The Management Company may be deemed the indirect beneficial owner of the reported shares, and the Reporting Person may be deemed the indirect beneficial owner of the reported shares through his interest in the Management Company. The Reporting Person disclaims beneficial ownership of the reported shares except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Madison Jones, Attorney-in-Fact</signatureName>
        <signatureDate>2021-03-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
